If α, β are the zeroes of a polynomial 3xsquare+6x-1, find α+β and αβ and hence find α/β^ +β/α^.
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Question
If α, β are the zeroes of a polynomial 3x² + 6x - 1, find α+β and αβ and hence find α/β +β/α
Solution
Given :-
- Polynomial equation, 3x² + 6x - 1 = 0
- α and β are zeroes.
Find :-
- value of α+β and α.β
- Value of α/β +β/α .
Explanation
Using Formula
★ Sum of zeroes = -(Coefficient Of x )/(Coefficient of x²)
★ Product of zeroes = (Constant part)/(Coefficient of x²)
So,
==> Sum of Zeroes = -(6)/(3)
==> Sum of Zeroes = -2
==> α+β = - 2 -------------------Equ(1)
And,
==> Product of zeroes = -1/3
==> α.β = -1/3 ------------------Equ(2)
Squaring both side of equation (1)
==> (α+β)² = (- 2)²
==> α² + β² + 2α.β = 4
Keep value by equ(2)
==> α² + β² + 2* (-1/3) = 4
==> α² + β² = 5 + 2/3
==> α² + β² (5*3 + 2)/3
==> α² + β² = (15+2)/3
==> α² + β² = 17/3 ---------------------equ(3)
So, Now calculate
α/β +β/α
= (α² + β²)/α.β
Keep value by equ (2) & equ(3)
= (17/3)/(-1/3)
= 17/3 * (-3)
= -17 [ Ans]
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