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sin^{-1}\left ( \frac{x^{2}}{4} + \frac{y^{2}}{9} \right )+ cos^{-1}\left ( \frac{x}{2 \sqrt{2}}+\frac{y}{3 \sqrt{2}}-2 \right ) is equal to:

Option: 1

\frac{\pi}{2}


Option: 2

\pi


Option: 3

\frac{\pi}{\sqrt{2}}


Option: 4

\frac{3\pi}{2}


Answers (1)

best_answer

 

Domains and Ranges of Inverse Trigonometric Functions -

For \sin ^{-1}x

Domain \epsilon \left [ -1, 1 \right ]

Range \epsilon \left [ -\frac{\pi }{2}, \frac{\pi }{2} \right ]

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Domains and Ranges of Inverse Trigonometric Functions -

For \cos ^{-1}x

Domain \epsilon \left [ -1, 1 \right ]

Range \epsilon \left [ 0, \pi \right ]

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-1\leq \frac{x^{2}}{4}+\frac{y^{2}}{9}\leq 1 represents interior and the boundary of the ellipse \frac{x^{2}}{4}+\frac{y^{2}}{9}=1

Also -1\leq \frac{x}{2\sqrt{2}}+\frac{y}{3\sqrt{2}}-2\leq 1

 

i.e. \frac{x}{2\sqrt{2}}+\frac{y}{3\sqrt{2}}\geq 1 and \frac{x}{2\sqrt{2}}+\frac{y}{3\sqrt{2}}\leq 3     

\frac{x}{2\sqrt{2}}+\frac{y}{3\sqrt{2}}\geq 3represents the portion of xy plane

which contains only one point viz :

\left ( \sqrt{2},\frac{3}{\sqrt{2}} \right ) \; of\;\frac{x^{2}}{4}+\frac{y^{2}}{9}< 1

\therefore sin^{-1}\left ( \frac{x^{2}}{4} + \frac{y^{2}}{9} \right )+cos^{-1}\left ( \frac{x}{2\sqrt{2}} + \frac{y}{3\sqrt{2}}-2 \right )

=sin^{-1}\left ( \frac{1}{2} + \frac{1}{2} \right )+cos^{-1}\left ( \frac{1}{2} + \frac{1}{2}-2 \right )

 

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seema garhwal

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