MCQ
$\sin \left( {4{{\tan }^{ - 1}}\frac{1}{3}} \right) = $
  • A
    $\frac{{12}}{{25}}$
  • $\frac{{24}}{{25}}$
  • C
    $\frac{1}{5}$
  • D
    None of these

Answer

Correct option: B.
$\frac{{24}}{{25}}$
b
(b) $\sin \left( {4{{\tan }^{ - 1}}\frac{1}{3}} \right) = \sin \left[ {2{{\tan }^{ - 1}}\left( {\frac{{2/3}}{{1 - (1/9)}}} \right)} \right]$ 

$ = \sin \left[ {2{{\tan }^{ - 1}}\frac{3}{4}} \right] = \sin {\sin ^{ - 1}}\left( {\frac{{2 \times (3/4)}}{{1 + (9/16)}}} \right)$

$ = \frac{3}{2} \times \frac{{16}}{{25}} = \frac{{24}}{{25}}$ 

$\left( {\because 2{{\tan }^{ - 1}}x = {{\sin }^{ - 1}}\frac{{2x}}{{1 + {x^2}}}} \right)$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free