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If x = asin θ, and y = btanθ , then find the value of a2x2−b2y2\frac{a^2}{x^2} -\frac{b^2}{y^2 }x2a2​−y2b2​ .​
Question

If x = asin θ, and y = btanθ , then find the value of a2x2b2y2\frac{a^2}{x^2} -\frac{b^2}{y^2 } .​

A.

1

B.

2

C.

–1

D.

0

Correct option is A

Given:
x = a sin θ
y = b tan θ
Formula Used:
From trigonometric identity; 1 + cot2 θ = cosec2θ
Solution:
=>a2x2b2y2=a2(asinθ)2b2(btanθ)2 =>1sin2θ1tan2θ =>cosec2θcot2θ=> \frac{a^2 }{ x^2}- \frac{b^2}{ y^2} = \frac{a^2 }{ (a sin θ) ^2} -\frac{ b^2 }{ (b tan θ)^2} \\\ \\=>\frac{ 1 }{sin^2 θ} -\frac{ 1 }{ tan^2θ }\\\ \\=> cosec^2 θ - cot^2 θ​​
From trigonometric identity 

1+cot2θ=cosec2θ =>cosec2θcot2θ=11 + cot^2 θ = cosec^2θ \\\ \\=> cosec^2 θ - cot^2 θ = 1​​

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