Relation between Roots and Coefficients for Quadratic
If α, β are...
Question
If α,β are the roots of x2+px+q=0 and γ,δ are the roots of x2+px+r=0, then (α−γ)(α−δ)(β−γ)(β−δ)=
A
1
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B
q
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C
r
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D
q+r
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Solution
The correct option is A1 Since, α,β are the roots of x2+px+q=0 α+β=−p and αβ=q Also, γ,δ are roots of x2+px+r=0, γ+δ=−p and γδ=r Consider (α−γ)(α−δ)(β−γ)(β−δ) =α2−(γ+δ)α+γδβ2−(γ+δ)β+γδ =α2+pα+rβ2+pβ+r =−q+r−q+r(∵α,β are roots of x2+px+q=0) =1