Q) If 𝛼, β are zeroes of quadratic polynomial x2 + x – 2, find the value of ![]()
Ans: In the given polynomial equation f(x), to find zeroes, we will start with f(x) = 0
Therefore, x2 + x – 2 = 0
Step 1: Given that the roots of the polynomial are α and β.
We know that sum of roots (α + β) = ![]()
∴ α + β =
= – 1 …………(i)
Next, we know that the product of the roots (α x β) = ![]()
∴ α . β =
= – 2 ………… (ii)
Step 2: Next, we need to find the value of ![]()
Let’s solve this to simplify:
=
………(iii)
We know that (a + b)2 = a2 + b2 + 2 a b
or we can say that a2 + b2 = (a + b)2 – 2 a b
Therefore, α2 + β2 = (α + β)2 – 2 α β
Transferring this value in equation (iii), we get:
= ![]()
Step 3: Next, we transfer values of (α + β) and α β from equations (i) and (ii)
= ![]()
= ![]()
= ![]()
= ![]()
Therefore, the value of
is – ![]()
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