Inverse Trigonometric Functions Question 3

Question: $ \cos [ {{\cos }^{-1}}( \frac{-1}{7} )+{{\sin }^{-1}}( \frac{-1}{7} ) ]= $

[EAMCET 2003]

Options:

A) $ -1/3 $

B) 0

C) $ 1/3 $

D) $ 4/9 $

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Answer:

Correct Answer: B

Solution:

$ \cos { {{\cos }^{-1}}( \frac{-1}{7} )+{{\sin }^{-1}}( \frac{-1}{7} ) }=\cos \frac{\pi }{2}=0 $ .