If α and β are the roots of the equation ax² + bx + c =0, express the roots of the equation a³x² - ab²x + b²c = 0 in terms of α and β.
Answers
Given,
α and β are the roots of the equation ax²+bx+c=0.
To find,
the roots of the equation a³x² - ab²x + b²c = 0(in terms of α and β).
Solution,
We know that,
By dividing the equation by a³, we'll get:-
=>
=> x² - (α+ β)(αβ)x + (αβ)³= 0
=> x²- α²βx - αβ²x + (αβ)³ = 0
=> x(x - α²β) - αβ²(x + α²β)=0
=> (x-α²β) (x-αβ²) = 0
α²β and αβ² are the roots of the equation a³x² - ab²x + b²c = 0 in terms of α and β.
_______________________________________
α and β are the roots of the equation.
⇒ ax² + bx + c = 0.
As we know that,
Sum of the zeroes of the quadratic polynomial.
⇒ α + β = - b/a.
Products of the zeroes of the quadratic polynomial.
⇒ αβ = c/a.
Roots of the equation.
⇒ a³x² - ab²x + b²c = 0.
As we know that,
Let, γ and δ are the roots of the equation.
⇒ a³x² - ab²x + b²c = 0.
Sum of the zeroes of the quadratic polynomial.
⇒ γ + δ = - b/a.
⇒ γ + δ = - (-ab²)/a³ = ab²/a³.
⇒ γ + δ = (b²/a²) = (-b/a)² = (α + β)².
Products of the zeroes of the quadratic polynomial.
⇒ γδ = c/a.
⇒ γδ = (b²c/a³) = (b²/a²)(c/a).
⇒ γδ = (b/a)²(c/a) = (α + β)².(αβ).
⇒ (γ - δ)² = (γ + δ)² - 4γδ.
⇒ (γ - δ)² = [(α + β)²]² - 4(αβ)(α + β)².
⇒ (γ - δ)² = (α + β)⁴ - 4(αβ)(α + β)².
⇒ (γ - δ) = (α² - β²). - - - - - (1).
⇒ (γ + δ) = (α + β)².
⇒ (γ + δ) = α² + β² + 2αβ. - - - - - (2).
Adding equation (1) and (2), we get.
⇒ 2γ = 2α² + 2αβ.
⇒ γ = α² + αβ.
Put the values of γ = α² + αβ in equation (1), we get.
⇒ (γ - δ) = (α² - β²). - - - - - (1).
⇒ (α² + αβ) - δ = (α² - β²)
⇒ (α² + αβ) - (α² - β²) = δ.
⇒ α² + αβ - α² + β² = δ.
⇒ β² + αβ = δ.
Values of γ = α² + αβ. and β² + αβ = δ.
_______________________________________
hope it helps you:)