Question

$sin\left[3si{n}^{-1}\left(0.4\right)\right]=$ .......

• A. $0.466$
• B. $0.256$
• C. $0.944$
• D. $0.764$

Answer 1

Answer: (C)

Let $E=\sin \left[3{\sin }^{-1}(0.4)\right]$
put ${\sin }^{-1}(0.4)=\theta \Rightarrow \sin \theta =0.4$
$\therefore E=\sin (3\theta )=3\sin \theta -4{\sin }^3\theta$
$=3(0.4)-4(0.4{)}^3$
$=1.2-4(0.064)$
$=1.2-0.256$
$=0.944$