Examine, seeing the graph of the polynomials given below, whether they are a linear or quadratic polynomial or neither linear nor quadratic polynomial:
(i) (ii)
(iii) (iv)
(v) (vi)
(vii) (viii)
(i) In general, we know that for a linear polynomial ax + b, a≠0, the graph of y = ax + b is a straight line which intersects the x – axis at exactly one point.
And here, we can see that the graph of y = p(x) is a straight line and intersects the x – axis at exactly one point. Therefore, the given graph is of a Linear Polynomial.
(ii) Here, the graph of y = p(x) is a straight line and parallel to the x – axis . Therefore, the given graph is of a Linear Polynomial.
(iii) For any quadratic polynomial ax2 + bx + c, a ≠ 0, the graph of the corresponding equation y = a x2 + bx + c has one of the two shapes either open upwards like or open downwards like depending on whether a > 0 or a < 0. (These curves are called parabolas.)
Here, we can see that the shape of the graph is a parabola. Therefore, the given graph is of a Quadratic Polynomial.
(iv) For any quadratic polynomial ax2 + bx + c, a ≠ 0, the graph of the corresponding equation y = ax2 + bx + c has one of the two shapes either open upwards like or open downwards like depending on whether a > 0or a < 0. (These curves are called parabolas.)
Here, we can see that the shape of the graph is parabola. Therefore, the given graph is of a Quadratic Polynomial.
(v) The shape of the graph is neither a straight line nor a parabola. So, the graph is not of a linear polynomial nor a quadratic polynomial.
(vi) The given graph have a straight line but it doesn’t intersect at x – axis and the shape of the graph is also not a parabola. So, it is not a graph of a quadratic polynomial. Therefore, it is not a graph of linear polynomial or quadratic polynomial.
(vii) The shape of the graph is neither a straight line nor a parabola. So, the graph is not of a linear polynomial or a quadratic polynomial.
(viii) The shape of the graph is neither a straight line nor a parabola. So, the graph is not of a linear polynomial or a quadratic polynomial.
The graphs of y – p(x) are given in the figures below, where p(x) is a polynomial. Find the number of zeros in each case.
(i) (ii)
(iii) (iv)
(v) (vi)
(i) Here, the graph of y = p(x) intersects the x – axis at two points. So, the number of zeroes is 2.
(ii) Here, the graph of y = p(x) intersects the x – axis at three points. So, the number of zeroes is 3.
(iii) Here, the graph of y = p(x) intersects the x – axis at one point only. So, the number of zeroes is 1.
(iv) Here, the graph of y = p(x) intersects the x – axis at exactly one point. So, the number of zeroes is 1.
(v) Here, the graph of y = p(x) intersects the x – axis at two points. So, the number of zeroes is 2.
(vi) Here, the graph of y = p(x) intersects the x – axis at exactly one point. So, the number of zeroes is 1.
The graphs of y = p(x) are given in the figures below, where p(x) is a polynomial Find the number of zeroes in each case.
(i) (ii)
(iii) (iv)
(v) (vi)
(i) Here, the graph of y = p(x) intersect the x – axis at zero points. So, the number of zeroes is 0.
(ii) Here, the graph of y = p(x) intersects the x – axis at two points. So, the number of zeroes is 2.
(iii) Here, the graph of y = p(x) intersects the x – axis at four points. So, the number of zeroes is 4.
(iv) Here, the graph of y = p(x) does not intersects the x – axis. So, the number of zeroes is 0.
(v) Here, the graph of y = p(x) intersects the x – axis at two points. So, the number of zeroes is 2.
(vi) Here, the graph of y = p(x) intersects the x – axis at two points. So, the number of zeroes is 2.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
x2 – 3
Let f (x) = x2 – 3
Now, if we recall the identity
(a2 – b2) = (a – b)(a + b)
Using this identity, we can write
x2 – 3 = (x – √3) (x + √3)
So, the value of x2 – 3 is zero when x = √3 or x = – √3
Therefore, the zeroes of x2 – 3 are √3 and – √3.
Verification
Now,
Sum of zeroes = α + β = √3 + ( – √3) = 0 or
Product of zeroes = αβ = (√3)( – √3) = – 3 or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
2x2 – 8x + 6
Let f(x) = 2x2 – 8x + 6
By splitting the middle term, we get
f(x) = 2 x2 – (2 + 6)x + 6 [∵ – 8 = – (2 + 6) and 2×6 = 12]
= 2 x2 – 2x – 6x + 6
= 2x(x – 1) – 6(x – 1)
= (2x – 6) (x – 1)
On putting f(x) = 0, we get
(2x – 6) (x – 1) = 0
⇒2x – 6 = 0 or x – 1 = 0
⇒x = 3 or x = 1
Thus, the zeroes of the given polynomial 2 x2 – 8x + 6 are 1 and 3
Verification
Sum of zeroes = α + β = 3 + 1 = 4 or
Product of zeroes = αβ = (3)(1) = 3 or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
x2 – 2x – 8
Let f(x) = x2 – 2x – 8
By splitting the middle term, we get
f(x) = x2 – 4x + 2x – 8 [∵ – 2 = 2 – 4 and 2×4 = 8]
= x(x – 4) + 2(x – 4)
= (x + 2) (x – 4)
On putting f(x) = 0, we get
(x + 2) (x – 4) = 0
⇒ x + 2 = 0 or x – 4 = 0
⇒x = – 2 or x = 4
Thus, the zeroes of the given polynomial x2 – 2x – 8 are – 2 and 4
Verification
Sum of zeroes = α + β = – 2 + 4 = 2 or
Product of zeroes = αβ = ( – 2)(4) = – 8 or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
3x2 + 5x – 2
Let f(x) = 3x2 + 5x – 2
By splitting the middle term, we get
f(x) = 3x2 + (6 – 1)x – 2 [∵ 5 = 6 – 1 and 2×3 = 6]
= 3x2 + 6x – x – 2
= 3x(x + 2) – 1(x + 2)
= (3x – 1) (x + 2)
On putting f(x) = 0 , we get
(3x – 1) (x + 2) = 0
⇒ 3x – 1 = 0 or x + 2 = 0
or x = – 2
Thus, the zeroes of the given polynomial 3x2 + 5x – 2 are – 2 and
Verification
Sum of zeroes or
Product of zeroes or
=
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
3x2 – x – 4
Let f(x) = 3x2 – x – 4
By splitting the middle term, we get
f(x) = 3x2 – (4 – 3)x – 4 [∵ – 1 = 3 – 4 and 4×3 = 12]
= 3x2 + 3x – 4x – 4
= 3x(x + 1) – 4(x + 1)
= (3x – 4) (x + 1)
On putting f(x) = 0, we get
(3x – 4) (x + 1) = 0
⇒ 3x – 4 = 0 or x + 1 = 0
or x = – 1
Thus, the zeroes of the given polynomial 3x2 – x – 4 are – 1 and
Verification
Sum of zeroes or
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
x2 + 7x + 10
Let f(x) = x2 + 7x + 10
By splitting the middle term, we get
f(x) = x2 + 5x + 2x + 10 [∵ 7 = 2 + 5 and 2×5 = 10]
= x(x + 5) + 2(x + 5)
= (x + 2) (x + 5)
On putting f(x) = 0 , we get
(x + 2) (x + 5) = 0
⇒ x + 2 = 0 or x + 5 = 0
⇒x = – 2 or x = – 5
Thus, the zeroes of the given polynomial x2 + 7x + 10 are – 2 and – 5
Verification
Sum of zeroes = α + β = – 2 + ( – 5) = – 7 or
Product of zeroes = αβ = ( – 2)( – 5) = 10 or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
t2 – 15
Let f(x) = t2 – 15
Now, if we recall the identity
(a2 – b2) = (a – b)(a + b)
Using this identity, we can write
t2 – 15 = (t – √15) (x + √15)
So, the value of t2– 15 is zero when t = √15 or t = – √15
Therefore, the zeroes of t2– 15 are √15 and – √15.
Verification
Now,
Sum of zeroes = α + β = √15 + ( – √15) = 0 or
Product of zeroes = αβ = (√15)( – √15) = – 15 or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
4 s2 – 4s + 1
Let f(x) = 4 s2 – 4s + 1
By splitting the middle term, we get
f(x) = 4 s2 – (2 – 2)s + 1 [∵ – 4 = – (2 + 2) and 2×2 = 4]
= 4 s2 – 2s – 2s + 1
= 2s(2s – 1) – 1(2s – 1)
= (2s – 1) (2s – 1)
On putting f(x) = 0 , we get
(2s – 1) (2s – 1) = 0
⇒ 2s – 1 = 0 or 2s – 1 = 0
or
Thus, the zeroes of the given polynomial 4 s2 – 4s + 1 are and
Verification
Sum of zeroes or
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
8x2– 22x – 21
Let f(x) = 8x2 – 22x – 21
By splitting the middle term, we get
f(x) = 8x2 – 28x + 6x – 21
= 4x(2x – 7) + 3(2x – 7)
= (4x + 3) (2x – 7)
On putting f(x) = 0 , we get
(4x + 3) (2x – 7) = 0
⇒ 4x + 3 = 0 or 2x – 7 = 0
or
Thus, the zeroes of the given polynomial 8x2 – 22x – 21 are and
Verification
Sum of zeroes or
The product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
2x2 – 7x
Let f(x) = 2 x2 – 7x
In this the constant term is zero.
f(x) = 2 x2 – 7x
= x(2x – 7)
On putting f(x) = 0 , we get
x(2x – 7) = 0
⇒ 2x – 7 = 0 or x = 0
or x = 0
Thus, the zeroes of the given polynomial 2x2 – 7x are 0 and
Verification
Sum of zeroes or
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
10x2 + 3x – 1
Let f(x) = 10x2 + 3x – 1
By splitting the middle term, we get
f(x) = 10x2 – 2x + 5x – 1
= 2x(5x – 1) + 1(5x – 1)
= (2x + 1) (5x – 1)
On putting f(x) = 0, we get
(2x + 1) (5x – 1) = 0
⇒ 2x + 1 = 0 or 5x – 1 = 0
= or =
Thus, the zeroes of the given polynomial10x2 + 3x – 1 are and
Verification
Sum of zeroes
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
px2 + (2q – p2)x – 2pq, p≠0
Let f(x) = px2 + (2q – p2)x – 2pq
f(x) = px2 + 2qx – p2 x – 2pq
= x(px + 2q) – p(px + 2q)
= (x – p) (px + 2q)
On putting f(x) = 0, we get
(x – p) (px + 2q) = 0
⇒ x – p = 0 or px + 2q = 0
⇒x = p or =
Thus, the zeroes of the given polynomial px2 + (2q – p2)x – 2pq are p and
Verification
Sum of zeroes
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
x2 – (2a + b)x + 2ab
Let f(x) = x2 – (2a + b)x + 2ab
f(x) = x2 – 2ax – bx + 2ab
= x(x – 2a) – b(x – 2a)
= (x – 2a) (x – b)
On putting f(x) = 0 , we get
(x – 2a) (x – b) = 0
⇒ x – 2a = 0 or x – b = 0
⇒x = 2a or x = b
Thus, the zeroes of the given polynomial x2 – (2a + b)x + 2ab are 2a and b
Verification
Sum of zeroes = α + β = 2a + b or
Product of zeroes = αβ = 2a × b = 2ab or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients:
r2s2x2 + 6rstx + 9t2
Let f(x) = r2s2x2 + 6rstx + 9t2
Now, if we recall the identity
(a + b)2 = a2 + b2 + 2ab
Using this identity, we can write
r2s2x2 + 6rstx + 9t2 = (rsx + 3t)2
On putting f(x) = 0 , we get
(rsx + 3t)2 = 0
Thus, the zeroes of the given polynomial r2s2x2 + 6rstx + 9t2 are and
Verification
Sum of zeroes or
or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the quadratic polynomial 5x2 – 8x – 4 and verify the relationship between the zeroes and the coefficients of the polynomial.
Let f(x) = 5x2 – 8x – 4
By splitting the middle term, we get
f(x) = 5x2 – 10x + 2x – 4
= 5x(x – 2) + 2(x – 2)
= (5x + 2) (x – 2)
On putting f(x) = 0 we get
(5x + 2) (x – 2) = 0
⇒ 5x + 2 = 0 or x – 2 = 0
or x = 2
Thus, the zeroes of the given polynomial5x2 – 8x – 4 are and 2
Verification
Sum of zeroes or
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the quadratic polynomial 4 x2 – 4x – 3 and verify the relationship between the zeroes and the coefficients of the polynomial.
Let f(x) = 4 x2 – 4x – 3
By splitting the middle term, we get
f(x) = 4 x2 – 6x + 2x – 3
= 2x(2x – 3) + 1(2x – 3)
= (2x + 1) (2x – 3)
On putting f(x) = 0, we get
(2x + 1) (2x – 3) = 0
⇒ 2x + 1 = 0 or 2x – 3 = 0
or
Thus, the zeroes of the given polynomial4x2 – 4x – 3 are and
Verification
Sum of zeroes or
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
Find the zeroes of the quadratic polynomial √3 x2 – 8x + 4√3 .
Let f(x) = √3 x2 – 8x + 4√3
By splitting the middle term, we get
(x) = √3 x2 – 6x – 2x + 4√3
= √3 x(x – 2√3) – 2(x – 2√3)
= (√3 x – 2) (x – 2√3)
On putting f (x) = 0, we get
(√3 x – 2) (x – 2√3) = 0
⇒ √3 x – 2 = 0 or x – 2√(3 = 0)
or
Thus, the zeroes of the given polynomial√3 x2 – 8x + 4√3 are and 2
Verification
Sum of zeroes or
Product of zeroes or
So, the relationship between the zeroes and the coefficients is verified.
If α and β be the zeroes of the polynomial 2x2 + 3x – 6, find the values of
(i) α2 + β2 (ii) α2 + β2 + αβ
(iii) α2β + αβ2 (iv)
(v) (vi) α – β
(vii) α3 + β3 (viii)
Let the quadratic polynomial be 2 x2 + 3x – 6, and its zeroes are α and β.
We have
Here, a = 2 , b = 3 and c = – 6
….(1)
….(2)
(i) α2 + β2
We have to find the value of α2 + β2
Now, if we recall the identity
(a + b)2 = a2 + b2 + 2ab
Using the identity, we get
(α + β)2 = α2 + β2 + 2αβ
{from eqn (1) & (2)}
(ii) α2 + β2 + αβ
{ from part (i)}
and, we have αβ = – 3
So,
=
=
(iii) α2β + α β2
Firstly, take common, we get
αβ(α + β)
and we already know the value of and .
So, α2β + α β2 = αβ(α + β)
{from eqn (1) and (2)}
(iv)
Let’s take the LCM first then we get,
(v)
Let’s take the LCM first then we get,
{from part(i) and eqn (2)}
(vi)
Now, recall the identity
(a – b)2 = a2 + b2 – 2ab
Using the identity , we get
(α – β)2 = α2 + β2 – 2 αβ
{from part(i) and eqn (2)}
= =
(vii)
Now, recall the identity
(a + b)3 = a3 + b3 + 3a2 b + 3ab2
Using the identity, we get
⇒(α + β)3 = α3 + β3 + 3α2 β + 3αβ2
(viii)
Let’s take the LCM first then we get,
{from part(vii) and eqn (2)}
If α and β be the zeroes of the polynomial ax2 + bx + c, find the values of
(i)
(ii)
(ii)
Let the quadratic poynomial be ax2 + bx + c , and its zeroes be α and β.
We have
α + β = and α β =
(i)
We have to find the value of
Now, if we recall the identity
(a + b)2 = a2 + b2 + 2ab
Using the identity, we get
{from eqn (1) & (2)}
(ii)
Let’s take the LCM first then we get,
{}
(iii)
Now, recall the identity
(a + b)3 = a3 + b3 + 3a2 b + 3ab2
Using the identity, we get
⇒(α + β)3 = α3 + β3 + 3α2 β + 3αβ2
If α, β are the zeroes of the quadratic polynomial x2 + kx = 12, such that α – β = 1, find the value of k.
The given quadratic polynomial is x2 + kx = 12 and – = 1
If we rearrange the polynomial then we get
p(x) = x2 + kx – 12
We have,
and
So,
…(1)
…(2)
Now, if we recall the identities
(a + b)2 = a2 + b2 + 2ab
Using the identity, we get
(α + β)2 = α2 + β2 + 2 αβ
( – k)2 = α2 + β2 + 2( – 12)
⇒ α2 + β2 = k2 + 24 …(3)
Again, using the identity
(a – b)2 = a2 + b2 – 2ab
Using the identity, we get
(α – β)2 = α2 + β2 – 2 αβ
(1)2 = α2 + β2 – 2( – 12) {∵ (α – β) = 1}
⇒ α2 + β2 = 1 – 24
⇒ α2 + β2 = – 23 …(4)
From eqn (3) and (4), we get
k2 + 24 = – 23
⇒ k2 = – 23 – 24
⇒ k2 = – 47
Now the square can never be negative, so the value of k is imaginary.
If the sum of squares of the zeroes of the quadratic polynomial x2 – 8x + k is 40, find k.
Given : p(x) = x2 – 8x + k
α2 + β2 = 40
We have,
and
So,
…(1)
…(2)
Now, if we recall the identities
(a + b)2 = a2 + b2 + 2ab
Using the identity, we get
(α + β)2 = α2 + β2 + 2 αβ
(8)2 = + 2(k)
⇒2k = 64 – 40
= = 12
If one zero of the polynomial (α2 + 9) x2 + 13x + 6α is reciprocal of the other, find the value of a.
Let one zero of the given polynomial is
According to the given condition,
The other zero of the polynomial is
We have,
Product of zeroes,
⇒ α2 – 6α + 9 = 0
⇒ α2 – 3α – 3α + 9 = 0
⇒ α(α – 3) – 3(α – 3) = 0
⇒(α – 3)(α – 3) = 0
⇒(α – 3) = 0 & (α – 3) = 0
⇒ α = 3, 3
If the product of zeroes of the polynomial α2 – 6x – 6 is 4, find the value of a.
Given Product of zeroes, α β = 4
p(x) = α x2 – 6x – 6
to find: value of α
We know,
Product of zeroes ,
If (x + a) is a factor 2x2 + 2ax + 5x + 10, find a.
Given x + a is a factor of
So,g(x) = x + a
x + a = 0
⇒x = – a
Putting the value x = – a in the given polynomial, we get
2( – a)2 + 2a( – a) + 5( – a) + 10 = 0
2a2 – 2a2 – 5a + 10 = 0
– 5a + 10 = 0
a = 2
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively:
1,1
Given: Sum of zeroes = α + β = 1
Product of zeroes = αβ = 1
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (1)x + 1
= x2 – x + 1
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively:
0,3
Given: Sum of zeroes = α + β = 0
Product of zeroes = αβ = 3
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (0)x + 3
= x2 + 3
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively:
Given: Sum of zeroes = α + β = 1/4
Product of zeroes = αβ = – 1
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
=
=
=
We can consider 4x2 – x – 4 as required quadratic polynomial because it will also satisfy the given conditions.
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively:
4,1
Given: Sum of zeroes = = 4
Product of zeroes = = 1
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (4)x + 1
= x2 – 4x + 1
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively:
Given: Sum of zeroes
Product of zeroes = αβ = – 1
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
=
=
=
We can consider 3x2 – 10x – 3 as required quadratic polynomial because it will also satisfy the given conditions.
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively:
Given: Sum of zeroes
Product of zeroes
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
=
=
=
We can consider 2x2 + x – 1 as required quadratic polynomial because it will also satisfy the given conditions.
Find quadratic polynomial whose zeroes are :
3, – 3
Let the zeroes of the quadratic polynomial be
α = 3 , β = – 3
Then, α + β = 3 + ( – 3) = 0
αβ = 3 × ( – 3) = – 9
Sum of zeroes = α + β = 0
Product of zeroes = αβ = – 9
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (0)x + ( – 9)
= x2 – 9
Find quadratic polynomial whose zeroes are :
Let the zeroes of the quadratic polynomial be
Then,
Sum of zeroes = α + β = 2
Product of zeroes = =
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
=
=
=
We can consider 4x2 – 8x – 1 as required quadratic polynomial because it will also satisfy the given conditions.
Find quadratic polynomial whose zeroes are :
Let the zeroes of the quadratic polynomial be
α = 3 + √7, β = 3 – √7
Then, α + β = 3 + √7 + 3 – √7 = 6
αβ = (3 + √(7)) × (3 – √7) = 9 – 7 = 2
Sum of zeroes = α + β = 6
Product of zeroes = αβ = 2
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (6)x + 2
= x2 – 6x + 2
Find quadratic polynomial whose zeroes are :
Let the zeroes of the quadratic polynomial be
α = 1 + 2√3, β = 1 – 2√3
Then, α + β = 1 + 2√3 + 1 – 2√3 = 2
αβ = (1 + 2√3) × (1 – 2√3) = 1 – 12 = – 11
Sum of zeroes = α + β = 2
Product of zeroes = αβ = – 11
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (2)x + ( – 11)
= x2 – 2x – 11
Find quadratic polynomial whose zeroes are :
Let the zeroes of the quadratic polynomial be
Then,
Sum of zeroes
Product of zeroes
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
=
=
=
We can consider 9x2 – 12x + 1 as required quadratic polynomial because it will also satisfy the given conditions.
Find quadratic polynomial whose zeroes are :
Let the zeroes of the quadratic polynomial be
α = √2, β = 2√2
Then, α + β = √2 + 2√2 = √2 (1 + 2) = 3√2
αβ = √2× 2√2 = 4
Sum of zeroes = α + β = 3√2
Product of zeroes = αβ = 4
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (3√2)x + 4
= x2 – 3√2 x + 4
Find the quadratic polynomial whose zeroes are square of the zeroes of the polynomial x2 – x – 1.
et the zeroes of the polynomial x2 – x – 1 be α and β
We have,
and
So,
Now, according to the given condition,
α2 β2 = ( – 1)2 = 1
& (α + β)2 = α2 + β2 + 2 α β
α2 + β2 = (α + β)2 – 2αβ
α2 + β2 = (1)2 – 2( – 1)
α2 + β2 = 3
So, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (3)x + 1
= x2 – 3x + 1
If α and β be the zeroes of the polynomial x2 + 10x + 30, then find the quadratic polynomial whose zeroes are α + 2β and 2α + β.
Given : p(x) = x2 + 10x + 30
So, Sum of zeroes …(1)
Product of zeroes …(2)
Now,
Let the zeroes of the quadratic polynomial be
α^' = α + 2β , β' = 2α + β
Then, α’ + β’ = α + 2β + 2α + β = 3α + 3β = 3(α + β)
α'β’ = (α + 2β) ×(2α + β) = 2α2 + 2β2 + 5αβ
Sum of zeroes = 3(α + β)
Product of zeroes = 2α2 + 2β2 + 5αβ
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (3(α + β))x + 2α2 + 2β2 + 5αβ
= x2 – 3( – 10)x + 2 (α2 + β2) + 5(30) {from eqn (1) & (2)}
= x2 + 30x + 2(α2 + β2 + 2αβ – 2αβ) + 150
= x2 + 30x + 2 (α + β)2 – 4αβ + 150
= x2 + 30x + 2( – 10)2 – 4(30) + 150
= x2 + 30x + 200 – 120 + 150
= x2 + 30x + 230
So, the required quadratic polynomial is x2 + 30x + 230
If α and β be the zeroes of the polynomial x2 + 4x + 3, find the quadratic polynomial whose zeroes are and .
Given : p(x) = x2 + 4x + 3
So, Sum of zeroes …(1)
Product of zeroes …(2)
Now,
Let the zeroes of the quadratic polynomial be
Then,
Sum of zeroes
Product of zeroes
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= +
= {from eqn (1) & (2)}
= +
=
So, the required quadratic polynomial is 3x2 – 16x + 16
Find a quadratic polynomial whose zeroes are 1 and – 3. Verify the relation between the coefficients and zeroes of the polynomial.
Let the zeroes of the quadratic polynomial be
α = 1 , β = – 3
Then, α + β = 1 + ( – 3) = – 2
αβ = 1 × ( – 3) = – 3
Sum of zeroes = α + β = – 2
Product of zeroes = αβ = – 3
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – ( – 2)x + ( – 3)
= x2 + 2x – 3
Verification
Sum of zeroes = α + β = 1 + ( – 3) = – 2 or
Product of zeroes = αβ = (1)( – 3) = – 3 or
So, the relationship between the zeroes and the coefficients is verified.
Find the quadratic polynomial sum of whose zeroes in 8 and their product is 12. Hence find the zeroes of the polynomial.
Given: Sum of zeroes = α + β = 8
Product of zeroes = αβ = 12
Then, the quadratic polynomial
= x2 – (sum of zeroes)x + product of zeroes
= x2 – (8)x + 12
= x2 – 8x + 12
Now, we have
and
So,
Divide 2x3 + 3x + 1 by x + 2 and find the quotient and the reminder. Is q(x) a factor of 2x3 + 3x + 1 ?
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = 2x2 – 4x + 11
Remainder = – 21
No, 2x2 – 4x + 11 is not a factor of 2x3 + 3x + 1 because remainder ≠ 0
Divide 3x3 + x2 + 2x + 5 by 1 + 2x + x2 and find the quotient and the remainder. Is 1 + 2x + x2 a factor of 3x3 + x2 + 2x + 5
Dividend = 3x3 + x2 + 2x + 5
Divisor = x2 + 2x + 1
Now, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = 3x – 5
Remainder = 9x + 10
No, x2 + 2x + 1 is not a factor of 3x3 + x2 + 2x + 5 because remainder ≠ 0
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = x3 – 3x2 + 4x + 2 , g(x) = x – 1
p(x) = x3 – 3x2 + 4x + 2,g(x) = x – 1
Dividend = x3 – 3x2 + 4x + 2
Divisor = x – 1
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = x2 – 2x + 2
Remainder = 4
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = 4x3 – 3x2 + 2x + 3 , g(x) = x + 4
p(x) = 4x3 – 3x2 + 2x + 3,g(x) = x + 4
Dividend = 4x3 – 3x2 + 2x + 3
Divisor = x + 4
Here, dividend and divisor both are in the standard form.
Now, on dividing by we get the following division process
Quotient = 4x2 – 13x + 54
Remainder = – 213
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = 2x4 + 3x3 + 4x2 + 19x + 45, g(x) = x – 2
p(x) = 2x4 + 3x3 + 4x2 + 19x + 45, g(x) = x – 2
Dividend = 2x4 + 3x3 + 4x2 + 19x + 45
Divisor = x – 2
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process we get,
q(x) = 2x3+7x2+18x+55
r(x) = 155
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = x4 + 2x3 – 3x2 + x – 1, g(x) = x – 2
p(x) = x4 + 2x3 – 3x2 + x – 1, g(x) = x – 2
Dividend = x4 + 2x3 – 3x2 + x – 1
Divisor = x – 2
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process we get,
q(x) = x3+4x2+5x+11
r(x) = 21
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = x3 – 3x2– x + 3, g(x) = x2 – 4x + 3
p(x) = x3 – 3x2– x + 3, g(x) = x2 – 4x + 3
Dividend = x3 – 3x2– x + 3
Divisor = x2 – 4x + 3
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process we get,
q(x)= x + 1
r(x) = 0
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = x6 + x4 + x3 + x2 + 2x + 2, g(x) = x3 + 1
p(x) = x6 + x4 + x3 + x2 + 2x + 2, g(x) = x3 + 1
Dividend = x6 + x4 + x3 + x2 + 2x + 2
Divisor = x3 + 1
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process we get,
q(x) = x3 + x
r(x) = x2 + x + 2
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = x6 + 3x2 + 10 and g(x) = x3 + 1
p(x) = x6 + 3x2 + 10 , g(x) = x3 + 1
Dividend = x6 + 3x2 + 10
Divisor = x3 + 1
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process we get,
q(x) = x3 – 1
r(x) = 3x2 + 11
Divide the polynomial p(x) by the polynomial g(x) and find the quotient q(x) and remainder r(x) in each case :
p(x) = x4 + 1, g(x) = x + 1
p(x) = x4 + 1, g(x) = x + 1
Dividend = x4 + 1,
Divisor = x + 1
q(x) = x3 – x2 + x – 1
r(x) = 0
By division process, find the value of k for which x – 1 is a factor of x3 – 6x2 + 11x + k.
On dividing x3 – 6x2 + 11x + k by x – 1 we get,
Since x – 1 is a factor of x3 – 6x2 + 11x + k,
This means x – 1 divides the given polynomial completely.
→ 6 x + k = 0
→ k = – 6x
By division process, find the value of c for which 2x + 1 is a factor of 4x4 – 3x2 + 3x + c.
On dividing 4x4 – 3x2 + 3x + c by 2x + 1 we get,
Since 2x + 1 is a factor of 4x4 – 3x2 + 3x + c,
This means 2x + 1 divides the given polynomial completely,
→ 4x + c = o
→ c = – 4x
Apply Division Algorithm to find the quotient q(x) and remainder r(x) on dividing p(x) by g(x) as given below:
p(x) = 2x2 + 3x + 1, g(x) = x + 2
p(x) = 2x2 + 3x + 1, g(x) = x + 2
Dividend = 2x2 + 3x + 1,
Divisor = x + 2
Apply the division algorithm we get,
q(x) = 2x – 1
r(x) = 3
Apply Division Algorithm to find the quotient q(x) and remainder r(x) on dividing p(x) by g(x) as given below:
p(x) = x3 – 3x2 + 5x – 3, g(x) = x2 – 2
p(x) = x3 – 3x2 + 5x – 3, g(x) = x2 – 2
Dividend = x3 – 3x2 + 5x – 3,
Divisor = x2 – 2
On applying division algorithm, we get,
q(x) = x – 3
r(x) = 7x – 9
Apply Division Algorithm to find the quotient q(x) and remainder r(x) on dividing p(x) by g(x) as given below:
p(x) = x4 – 1 , g(x) = x + 1
p(x) = x4 – 1,g(x) = x + 1
Dividend = x4 – 1
Divisor = x + 1
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = x3 – x2 + x – 1
Remainder = 0
Apply Division Algorithm to find the quotient q(x) and remainder r(x) on dividing p(x) by g(x) as given below:
p(x) = x3 – 3x2 + 4x + 2 , g(x) = x – 1
p(x) = x3 – 3x2 + 4x + 2,g(x) = x – 1
Dividend = x3 – 3x2 + 4x + 2
Divisor = x – 1
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = x – 5
Remainder = 13x + 7
Apply Division Algorithm to find the quotient q(x) and remainder r(x) on dividing p(x) by g(x) as given below:
p(x) = x3 – 6x2 + 11x – 6 , g(x) = x2 – 5x + 6
p(x) = x3 – 6x2 + 11x – 6,g(x) = x2 – 5x + 6
Dividend = x3 – 6x2 + 11x – 6
Divisor = x2 – 5x + 6
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = x – 1
Remainder = 6x
Apply Division Algorithm to find the quotient q(x) and remainder r(x) on dividing p(x) by g(x) as given below:
p(x) = 6x3 + 13x2 + x – 2 , g(x) = 2x + 1
p(x) = 6x3 + 13x2 + x – 2,g(x) = 2x + 1
Dividend = 6x3 + 13x2 + x – 2
Divisor = 2x + 1
Here, dividend and divisor both are in the standard form.
Now, on dividing p(x) by g(x) we get the following division process
Quotient = 3x2 + 5x – 2
Remainder = 0
Applying the Division Algorithm, check whether the first polynomial is a factor of the second polynomial:
x – 2, x3 + 3x3 – 12x + 4
Let us divide x3 + 3x2 – 12x + 4 by x – 2
The division process is
Here, the remainder is 0, therefore x – 2 is a factor of x3 + 3x2 – 12x + 4
Applying the Division Algorithm, check whether the first polynomial is a factor of the second polynomial:
x2 + 3x + 1,3x4 + 5x3 – 7x2 + 2x + 2
Let us divide 3x4 + 5x3 – 7x2 + 2x + 2 by x2 + 3x + 1
The division process is
Here, the remainder is 0, therefore x2 + 3x + 1 is a factor of 3x4 + 5x3 – 7x2 + 2x + 2
Applying the Division Algorithm, check whether the first polynomial is a factor of the second polynomial:
x2 – 3x + 4,2x4 – 11x3 + 29x2 – 30x + 29
Let us divide 2x4 – 11x3 + 29x2 – 30x + 29 by x2 – 3x + 4
The division process is
Here, the remainder is 58x – 115 , therefore x2 – 3x + 4 is not a factor of 2x4 – 11x3 + 29x2 – 30x + 29
Applying the Division Algorithm, check whether the first polynomial is a factor of the second polynomial:
x2 – 4x + 3,x3 – x3 – 3x4 – x + 3
Let us divide x3 – 3x2 – x + 3 by x2 – 4x + 3
The division process is
Here, the remainder is 0, therefore x2 – 4x + 3 is a factor of x3 – 3x2 – x + 3
Applying the Division Algorithm, check whether the first polynomial is a factor of the second polynomial:
t – 1, t3 + t2 – 2t + 1
Let us divide t3 + t2 – 2t + 1 by t – 1
The division process is
Here, the remainder is 1, therefore t – 1 is not a factor of t3 + t2 – 2t + 1
Applying the Division Algorithm, check whether the first polynomial is a factor of the second polynomial:
t2 – 5t + 6,t2 + 11t – 6
Let us divide t2 + 11t – 6 by t2 – 5t + 6
The division process is
Here, the remainder is 16t – 12,
Therefore, t2 – 5t + 6 is not a factor of t2 + 11t – 6
Give examples of polynomials p(x), g(x), q(x) and r(x) satisfying the Division Algorithm
p(x) = g(x).q(x) + r(x),deg r(x)<deg g(x)
And also satisfying
(i) deg p(x) = deg q(x) + 1
(ii)deg q(x) = 1
(iii) deg q(x) = deg r(x) + 1
(i)Let p(x) = 12x2 + 8x + 25, g(x) = 4,
q(x) = 3x2 + 2x + 6 , r(x) = 0
Here, degree p(x) = degree q(x) = 2
Now, g(x).q(x) + r(x) = (3x2 + 2x + 6)×4 + 1
= 12x2 + 8x + 24 + 1
= 12x2 + 8x + 25
(ii) Let p(x) = t3 + t2 – 2t, g(x) = t2 + 2t,
q(x) = t – 1 , r(x) = 0
Here, degree q(x) = 1
Now, g(x).q(x) + r(x) = (t2 + 2t)×(t – 1) + 0
= t3 – t2 + 2t2 – 2t
= t3 + t2 – 2t
(iii) Let p(x) = x3 + x2 + x + 1 , g(x) = x2 – 1,
q(x) = x + 1 , r(x) = 2x + 2
Here, degree q(x) = degree r(x) + 1 = 1
Now, g(x).q(x) + r(x) = (x2 – 1)×(x + 1) + 2x + 2
= x3 + x2 – x – 1 + 2x + 2
= x3 + x2 + x + 1
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
x3 – 6x2 + 11x – 6;3
Given zeroes is 3
So, (x – 3) is the factor of x3 – 6x2 + 11x – 6
Let us divide x3 – 6x2 + 11x – 6 by x – 3
The division process is
Here, quotient = x2 – 3x + 2
= x2 – 2x – x + 2
= x(x – 2) – 1(x – 2)
= (x – 1)(x – 2)
So, the zeroes are 1 and 2
Hence, all the zeroes of the given polynomial are 1, 2 and 3.
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
x4 – 8x3 + 23x2 – 28x + 12;1,2
Given zeroes are 1 and 2
So, (x – 1)and (x – 2) are the factors of x4 – 8x3 + 23x2 – 28x + 12
⟹ (x – 1)(x – 2) = x2 – 3x + 2 is a factor of given polynomial.
Consequently, x2 – 3x + 2 is also a factor of the given polynomial.
Now, let us divide x4 – 8x3 + 23x2 – 28x + 12 by x2 – 3x + 2
The division process is
Here, quotient = x2 – 5x + 6
= x2 – 2x – 3x + 6
= x(x – 2) – 3(x – 2)
= (x – 3)(x – 2)
So, the zeroes are 3 and 2
Hence, all the zeroes of the given polynomial are 1, 2 ,2 and 3.
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
x3 + 2x2 – 2; – 2
Given zeroes is – 2
So, (x + 2) is the factor of x3 + 2x2 – x – 2
Let us divide x3 + 2x2 – x – 2 by x + 2
The division process is
Here, quotient = x2 – 1
= (x – 1)(x + 1)
So, the zeroes are – 1 and 1
Hence, all the zeroes of the given polynomial are – 1, – 2 and 1.
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
x3 + 5x2 + 7x + 3; – 3
Given zeroes is – 3
So, (x + 3) is the factor of x3 + 5x2 + 7x + 3
Let us divide x3 + 5x2 + 7x + 3 by x + 3
The division process is
Here, quotient = x2 + 2x + 1
= (x + 1)2
So, the zeroes are – 1 and – 1
Hence, all the zeroes of the given polynomial are – 1, – 1 and – 3.
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
x4 – 6x3 – 26x2 + 138x – 35;2±√3
x4 – 6x3 – 26x2 + 138x – 35;2±√3
Given zeroes are 2 + √3 and 2 – √3
So, (x – 2 – √3)and (x – 2 + √3) are the factors of x4 – 6x3 – 26x2 + 138x – 35
⟹ (x – 2 – √3)(x – 2 + √3)
= x2 – 2x + √3 x – 2x + 4 – 2√3 – √3 x + 2√3 – 3
= x2 – 4x + 1 is a factor of given polynomial.
Consequently, x2 – 4x + 1 is also a factor of the given polynomial.
Now, let us divide x4 – 6x3 – 26x2 + 138x – 35 by x2 – 4x + 1
The division process is
Here, quotient = x2 – 2x – 35
= x2 – 7x + 5x – 35
= x(x – 7) + 5(x – 7)
= (x + 5)(x – 7)
So, the zeroes are – 5 and 7
Hence, all the zeroes of the given polynomial are – 5, 7, 2 + √3 and
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
x4 + x3 – 34x2 – 4x + 120;2, – 2.
x4 + x3 – 34x2 – 4x + 120;2, – 2.
Given zeroes are – 2 and 2
So, (x + 2)and (x – 2) are the factors of x4 + x3 – 34x2 – 4x + 120
⟹ (x + 2)(x – 2) = x2 – 4 is a factor of given polynomial.
Consequently, x2 – 4 is also a factor of the given polynomial.
Now, let us divide x4 + x3 – 34x2 – 4x + 120 by x2 – 4
The division process is
Here, quotient = x2 + x – 30
= x2 + 6x – 5x – 30
= x(x + 6) – 5(x + 6)
= (x + 6)(x – 5)
So, the zeroes are – 6 and 5
Hence, all the zeroes of the given polynomial are – 2 , – 6, 2 and 5.
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
2x4 + 7x3 – 19x2 – 14x + 30;√(2, – √2)
2x4 + 7x3 – 19x2 – 14x + 30;√(2, – √2)
Given zeroes are √2 and – √2
So, (x – √2)and (x + √2) are the factors of 2x4 + 7x3 – 19x2 – 14x + 30
⟹ (x – √2)(x + √2) = x2 – 2 is a factor of given polynomial.
Consequently, x2 – 2 is also a factor of the given polynomial.
Now, let us divide 2x4 + 7x3 – 19x2 – 14x + 30 by x2 – 2
The division process is
Here, quotient = 2x2 + 7x – 15
= 2x2 + 10x – 3x – 15
= 2x(x + 5) – 3(x + 5)
= (2x – 3)(x + 5)
So, the zeroes are – 5 and
Hence, all the zeroes of the given polynomial are – 5, – √2, √2 and
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
2x4 – 9x3 + 5x2 + 3x – 1;2±√3
2x4 – 9x3 + 5x2 + 3x – 1;2±√3
Given zeroes are 2 + √3 and 2 – √3
So, (x – 2 – √3)and (x – 2 + √3) are the factors of 2x4 – 9x3 + 5x2 + 3x – 1
⟹ (x – 2 – √3)(x – 2 + √3)
= x2 – 2x + √3 x – 2x + 4 – 2√3 – √3 x + 2√3 – 3
= x2 – 4x + 1 is a factor of given polynomial.
Consequently, x2 – 4x + 1 is also a factor of the given polynomial.
Now, let us divide 2x4 – 9x3 + 5x2 + 3x – 1 by x2 – 4x + 1
The division process is
Here, quotient = 2x2 – x – 1
= 2x2 – 2x + x – 1
= 2x(x – 1) + 1(x – 1)
= (2x + 1)(x – 1)
So, the zeroes are and 1
Hence, all the zeroes of the given polynomial are , 1, 2 + √3 and 2 – √3
Find all the zeroes of the polynomial given below having given numbers as its zeroes.
2x3 – 4x – x2 + 2;√2, – √2
2x3 – 4x – x2 + 2;√2, – √2
Given zeroes are √2 and – √2
So, (x – √2) and (x + √2) are the factors of 2x3 – 4x – x2 + 2
⟹ (x – √2)(x + √2) = x2 – 2 is a factor of given polynomial.
Consequently, x2 – 2 is also a factor of the given polynomial.
Now, let us divide 2x3 – 4x – x2 + 2by x2 – 2
The division process is
Here, quotient = 2x – 1
So, the zeroes is
Hence, all the zeroes of the given polynomial are , and
Verify that are the zeroes of the cubic polynomial p(x) = 3x2 – 5x2 – 11x – 3 and then verify the relationship between the zeroes and the coefficients.
Let p(x) = 3 x3 – 5 x2 – 11x – 3
Then, p( – 1) = 3( – 1)3 – 5( – 1)2 – 11( – 1) – 3
= – 3 – 5 + 11 – 3
= 0
= 0
p(3) = 3(3)3 – 5(3)2 – 11(3) – 3
= 81 – 45 – 33 – 3
= 0
Hence, we verified that 3, – 1 and are the zeroes of the given polynomial.
So, we take α = 3, β = – 1,
Verification
α + β + γ
αβ + βγ + γα
and αβγ
= 1
Thus, the relationship between the zeroes and the coefficients is verified.
Verify that the numbers given alongside of the cubic polynomial are their zeros. Also verify the relationship between the zeroes and the coefficients in each case :
x3 – 4x2 + 5x – 2;2, 1, 1
Let p(x) = x3 – 4x2 + 5x – 2
Then, p(2) = (2)3 – 4(2)2 + 5(2) – 2
= 8 – 16 + 10 – 2
= 0
p(1) = (1)3 – 4(1)2 + 5(1) – 2
= 1 – 4 + 5 – 2
= 0
Hence, 2, 1 and 1 are the zeroes of the given polynomial x3 – 4x2 + 5x – 2.
Now, Let α = 2 , β = 1 and γ = 1
Then, α + β + γ = 2 + 1 + 1 = 4
αβ + βγ + γα = (2)(1) + (1)(1) + (1)(2)
= 2 + 1 + 2
= 5
and αβγ = 2 × 1 × 1
= 2
Thus, the relationship between the zeroes and the coefficients is verified.
Verify that the numbers given alongside of the cubic polynomial are their zeros. Also verify the relationship between the zeroes and the coefficients in each case :
x3 – 6x2 + 11x – 6 ;1, 2, 3
Let p(x) = x3 – 6x2 + 11x – 6
Then, p(1) = (1)3 – 6(1)2 + 11(1) – 6
= 1 – 6 + 11 – 6
= 0
p(2) = (2)3 – 6(2)2 + 11(2) – 6
= 8 – 24 + 22 – 6
= 0
p(3) = (3)3 – 6(3)2 + 11(3) – 6
= 27 – 54 + 33 – 6
= 0
Hence, 1, 2 and 3 are the zeroes of the given polynomial x3 – 6x2 + 11x – 6.
Now, Let α = 1 , β = 2 and γ = 3
Then, α + β + γ = 1 + 2 + 3 = 6
αβ + βγ + γα = (1)(2) + (2)(3) + (3)(1)
= 2 + 6 + 3
= 11
and αβγ = 1 × 2 × 3
= 6
Thus, the relationship between the zeroes and the coefficients is verified.
Verify that the numbers given alongside of the cubic polynomial are their zeros. Also verify the relationship between the zeroes and the coefficients in each case :
x3 + 2x2 – x – 2; – 2 – 2, 1
Let p(x) = x3 + 2x2 – x – 2
Then, p( – 2) = ( – 2)3 + 2( – 2)2 – ( – 2) – 2
= – 8 + 8 + 2 – 2
= 0
p(1) = (1)3 + 2(1)2 – (1) – 2
= 1 + 2 – 1 – 2
= 0
Hence, – 2, – 2 and 1 are the zeroes of the given polynomial x3 + 2x2 – x – 2.
Now, Let α = – 2 , β = – 2 and γ = 1
Then, α + β + γ = – 2 + ( – 2) + 1 = – 3
αβ + βγ + γα = ( – 2)( – 2) + ( – 2)(1) + (1)( – 2)
= 4 – 2 – 2
= 0
and αβγ = ( – 2) × ( – 2) × 1
= 4
Thus, the relationship between the zeroes and the coefficients is not verified.
Verify that the numbers given alongside of the cubic polynomial are their zeros. Also verify the relationship between the zeroes and the coefficients in each case :
x3 + 5x2 + 7x + 3 ; – 3, 2 – 1, – 1
Let p(x) = x3 + 5x2 + 7x + 3.
Then, p( – 1) = ( – 1)3 + 5( – 1)2 + 7( – 1) + 3
= – 1 + 5 – 7 + 3
= 0
p( – 3) = ( – 3)3 + 5( – 3)2 + 7( – 3) + 3
= – 27 + 45 – 21 + 3
= 0
Hence, – 1, – 1 and – 3 are the zeroes of the given polynomial x3 + 5x2 + 7x + 3.
Now, Let α = – 1 , β = – 1 and γ = – 3
Then, α + β + γ = – 1 + ( – 1) + ( – 3) = – 5
αβ + βγ + γα = ( – 1)( – 1) + ( – 1)( – 3) + ( – 3)( – 1)
= 1 + 3 + 3
= 7
and αβγ = ( – 1) × ( – 1) × ( – 3)
= – 3
Thus, the relationship between the zeroes and the coefficients is verified.
Find a cubic polynomial having 1, 2, 3 as its zeroes.
Let the zeroes of the cubic polynomial be
α = 1, β = 2 and γ = 3
Then, α + β + γ = 1 + 2 + 3 = 6
αβ + βγ + γα = (1)(2) + (2)(3) + (3)(1)
= 2 + 6 + 3
= 11
and αβγ = 1 × 2 × 3
= 6
Now, required cubic polynomial
= x3 – (α + β + γ) x2 + (αβ + βγ + γα)x – αβγ
= x3 – (6) x2 + (11)x – 6
= x3 – 6 x2 + 11x – 6
So, x3 – 6 x2 + 11x – 6 is the required cubic polynomial which satisfy the given conditions.
Find a cubic polynomial having – 3, – 2, 2 as its zeroes.
Let the zeroes of the cubic polynomial be
α = – 3, β = – 2 and γ = 2
Then, α + β + γ = – 3 + ( – 2) + 2
= – 3 – 2 + 2
= – 3
αβ + βγ + γα = ( – 3)( – 2) + ( – 2)(2) + (2)( – 3)
= 6 – 4 – 6
= – 4
and αβγ = ( – 3) × ( – 2) × 2
= 6 × 2
= 12
Now, required cubic polynomial
= x3 – (α + β + γ) x2 + (αβ + βγ + γα)x – αβγ
= x3 – ( – 3) x2 + ( – 4)x – 12
= x3 + 3 x2 – 4x – 12
So, x3 + 3x^2 – 4x – 12 is the required cubic polynomial which satisfy the given conditions.
Find a cubic polynomial with the sum of its zeroes are 0, – 7 and – 6 respectively.
Let the zeroes be α, β and γ.
Then, we have
α + β + γ = 0
αβ + βγ + γα = – 7
and αβγ = – 6
Now, required cubic polynomial
= x3 – (α + β + γ) x2 + (αβ + βγ + γα)x – αβγ
= x3 – (0) x2 + ( – 7)x – ( – 6)
= x3 – 7x + 6
So, x3 – 7x + 6 is the required cubic polynomial.
Find a cubic polynomial with the sum of its zeroes, sum of the products of its zeroes taken two at a time and product of its zeroes as the numbers given below:
2, – 7, – 14
Let the zeroes be α, β and γ.
Then, we have
α + β + γ = 2
αβ + βγ + γα = – 7
and αβγ = – 14
Now, required cubic polynomial
Sox3 – 2x2 – 7x + 14 is the required cubic polynomial.
Find a cubic polynomial with the sum of its zeroes, sum of the products of its zeroes taken two at a time and product of its zeroes as the numbers given below:
Let the zeroes be α, β and γ.
Then, we have
Now, required cubic polynomial
So, 6x3 + 24x2 + 3x – 2 is the required cubic polynomial which satisfy the given conditions.
Find a cubic polynomial with the sum of its zeroes, sum of the products of its zeroes taken two at a time and product of its zeroes as the numbers given below:
Let the zeroes be α, β and γ.
Then, we have
Now, required cubic polynomial
So, 7x3 – 5x2 + x – 1 is the required cubic polynomial which satisfy the given conditions.
Find a cubic polynomial with the sum of its zeroes, sum of the products of its zeroes taken two at a time and product of its zeroes as the numbers given below:
Let the zeroes be α, β and γ.
Then, we have
Now, required cubic polynomial
So, 10x3 – 4x2 + x – 5 is the required cubic polynomial which satisfy the given conditions.