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Please Solve R.D.Sharma Class 12 Chapter 10 Differentiation Exercise 10.3  Question 10 Maths Textbook Solution.

Answers (1)

Answer: \frac{d y}{d x}=1

Hint:

\frac{\mathrm{d}}{\mathrm{d} \mathrm{x}} \text { (constants) }=0

\frac{d}{d\mathrm{x}}\left(\mathrm{x}^{\mathrm{n}}\right)=\mathrm{nx}^{\mathrm{n}-1}

Given:

\sin ^{-1}\left\{\frac{\sin x+\cos x}{\sqrt{2}}\right\}

\frac{-3 \mathrm{\pi}}{4}<\mathrm{x}<\frac{\pi}{4}

Soluton:

Let,y=\sin ^{-1}\left\{\frac{\sin x+\cos x}{\sqrt{2}}\right\}

Now,

\mathrm{y}=\sin ^{-1}\left\{\sin \mathrm{x} \frac{1}{\sqrt{2}}+\cos \mathrm{x} \frac{1}{\sqrt{2}}\right\}

\mathrm{y}=\sin ^{-1}\left\{\sin \mathrm{x} \cos \left(\frac{\mathrm{\pi}}{4}\right)+\cos \mathrm{xsin}\left(\frac{\mathrm{\pi}}{4}\right)\right\}

\sin \left(\frac{\mathrm{\pi}}{4}\right)=\frac{1}{\sqrt{2}} \&

\cos \left(\frac{\pi}{4}\right)=\frac{1}{\sqrt{2}}

Using,

  \sin (A+B)=\sin A \cos B+\cos A \sin B

\mathrm{y}=\sin ^{-1}\left\{\sin \left(\mathrm{x}+\frac{\pi}{4}\right)\right\}

Considering the limits,

-\frac{3 \pi}{4}<x<\frac{\pi}{4}

-\frac{3 \pi}{4}+\frac{\pi}{4}<x+\frac{\pi}{4}<\frac{\pi}{4}+\frac{1}{4}

-\frac{\mathrm{\pi}}{2}<\mathrm{x}+\frac{\mathrm{\pi}}{4}<\frac{\pi}{2}

Now,

\mathrm{y}=\sin ^{-1}\left\{\sin \left(\mathrm{x}+\frac{\mathrm{\pi}}{4}\right)\right\}

y=x+\frac{\pi}{4}                                                                                                                                                                                \left\{\sin ^{-1}(\sin \theta)=\theta, \text { if } \theta \varepsilon\left[\frac{\pi}{2}, \frac{\pi}{2}\right]\right\}

Differentiating with respect to x , We get

\frac{d y}{d x}=1+0

\frac{\mathrm{d}}{\mathrm{dx}} \text { (constant) }=0

\frac{d y}{d x}=1

 

 

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