Q) If 𝛼, β are zeroes of quadratic polynomial x2 – 2x + 3, find the polynomial whose roots are:
1. 𝛼 + 2, 𝛽 + 2
2.
Ans: Given polynomial equation x2 – 2x + 3 = 0
Comparing with standard polynomial, ax2 + b x + c = 0, we get,
a = 1, b = – 2, c = 3
Since, its given that the roots of the polynomial be α and β.
and we know that sum of roots (α + β) =
α + β = = 2 …………… (i)
Also, we know that the product of the roots (α x β) =
α . β = = 3 …………. (ii)
Next, Let’s find the polynomials:
(1) Polynomial for roots (𝛼 + 2, 𝛽 + 2):
∵ Sum of the zeroes of new polynomial = (α + 2) + (β + 2) = (α + β) + 4
By transferring values from equations (i), we get:
∴ Sum of the zeroes of new polynomial = (2) + 4 = 6
Next, Product of the zeroes of new polynomial = (α + 2)(β + 2)
= αβ + 2α + 2β + 4
= αβ + 2(α + β) + 4
∴ Product of the zeroes of new polynomial = (3) + 2 (2) + 4 = 11
Since, quadratic polynomial f(x) = x2 – (sum of the zeroes)x + (product of the zeroes)
= x2 – (6) x + (11)
Hence, the required quadratic polynomial is f(x) = x2 – 6x + 11
(2) Polynomial for roots ()
∵ Sum of the zeroes of new polynomial =
=
=
=
By transferring values from equations (i) and (ii), we get:
∴ Sum of the zeroes of new polynomial = =
∴ Sum of the zeroes of new polynomial =
Next, Product of the zeroes of new polynomial =
=
=
=
By transferring values from equations (i) and (ii), we get:
Product of the zeroes of new polynomial = =
∴ Product of the zeroes of new polynomial =
Since, quadratic polynomial f(x) = x2 – (sum of the zeroes)x + (product of the zeroes)
= x2 – x +
Hence, the required quadratic polynomial is f(x) = x2 – x +