Get Answers to all your Questions

header-bg qa

Provide solution for RD Sharma maths class 12 chapter Differentiation exercise 10.8 question 10

Answers (1)


Answer: \frac{1}{a x \sqrt{1+a^{2} x^{2}}}

Hint:   \text { Let } u=\tan ^{-1}\left(\frac{1+a x}{1-a x}\right), v=\sqrt{1+a^{2} x^{2}}
Given:  \tan ^{-1}\left(\frac{1+a x}{1-a x}\right) \text { w.r.t } \sqrt{1+a^{2} x^{2}}

Explanation:  \text { Let } u=\tan ^{-1}\left(\frac{1+a x}{1-a x}\right)

\begin{aligned} &v=\sqrt{1+a^{2} x^{2}} \\\\ &\text { Let } a x=\tan \theta \\\\ &u=\tan ^{-1}\left(\frac{1+\tan \theta}{1-\tan \theta}\right) \end{aligned}

   =\tan ^{-1}\left(\frac{\tan \frac{\pi}{4}+\tan \theta}{1-\tan \frac{\pi}{4} \tan \theta}\right) \quad\left[\tan \frac{\pi}{4}=1\right]

   \begin{aligned} &=\tan ^{-1} \tan \left(\frac{\pi}{4}+\theta\right) \\\\ &=\frac{\pi}{4}+\theta \end{aligned}

u=\frac{\pi}{4}+\tan ^{-1}(a x) \; \; \; \; \; \; \; \quad\left[\begin{array}{l} a x=\tan \theta \\ \theta=\tan ^{-1} a x \end{array}\right]

\begin{aligned} &\frac{d u}{d x}=\frac{1}{1+(a x)^{2}}[a \times 1] \\\\ &=\frac{a}{1+a^{2} x^{2}} \\\\ &v=\sqrt{1+a^{2} x^{2}} \end{aligned}

\begin{aligned} &\frac{d v}{d x}=\frac{1}{2 \sqrt{1+a^{2} x^{2}}} \frac{d}{d x}\left(a^{2} x^{2}\right) \\\\ &=\frac{2 a^{2} x}{2 \sqrt{1+a^{2} x^{2}}}=\frac{a^{2} x}{\sqrt{1+a^{2} x^{2}}} \end{aligned}

\frac{d u}{d v}=\frac{\frac{d u}{d x}}{\frac{d v}{d x}}

=\frac{\frac{a}{1+a^{2} x^{2}}}{\frac{a^{2} x}{\sqrt{1+a^{2} x^{2}}}}=\frac{1}{a x \sqrt{1+a^{2} x^{2}}}



Posted by


View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support