Foundation
Mathematics Foundation
Introduction to Trigonometry
Question

If tanθ=ab then (asinθbcosθ)(asinθ+bcosθ)=?

(a2+b2)(a2b2)

b2(a2+b2)

a2(a2+b2)

(a2-b2)(a2+b2)

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Solution

Given tanθ = a/b, we can represent sinθ and cosθ in terms of a and b. Let sinθ = a/√(a²+b²) and cosθ = b/√(a²+b²).

Substitute into the expression:

(asinθ-bcosθ)(asinθ+bcosθ)=a·aa2+b2-b·ba2+b2a·aa2+b2+b·ba2+b2=a2-b2a2+b2

Final Answer: (a2-b2)(a2+b2)