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Question

Mathematics Question on Inverse Trigonometric Functions

If sin1x+sin1y=π2\sin^{-1} \, x + \sin^{-1} \,y= \frac{\pi}{2} , then x2x^2 is equal to

A

1y21 - y^2

B

y2y^2

C

00

D

1y\sqrt{1 - y }

Answer

1y21 - y^2

Explanation

Solution

We have, sin1x+sin1y=π2\sin ^{-1} x+\sin ^{-1} y=\frac{\pi}{2}
sin1x=π2sin1y\Rightarrow \sin ^{-1} x=\frac{\pi}{2}-\sin ^{-1} y
sin1x=cos1y\Rightarrow \sin ^{-1} x=\cos ^{-1} y
[sin1x+cos1x=π2]\left[\because \sin ^{-1} x+\cos ^{-1} x=\frac{\pi}{2}\right]
sin1x=sin1(1y2)\Rightarrow \sin ^{-1} x=\sin ^{-1}\left(\sqrt{1-y^{2}}\right)
x=1y2\Rightarrow x=\sqrt{1-y^{2}}
x2=1y2\Rightarrow x^{2}=1-y^{2}