Question

If sin^–1 x = $\frac{\pi}{5}$ for some x Î (–1, 1) then the value of cos^–1 x is

• A. $\frac{3\pi}{10}$
• B. $\frac{5\pi}{10}$
• C. $\frac{7\pi}{10}$
• D. $\frac{9\pi}{10}$

Answer 1

Answer: (A)

$\frac{3\pi}{10}$

Answer 2

sin^–1 x + cos^–1 x = p/2