If $$\sum\limits_{i = 1}^{10} {{{\cos }^{ - 1}}{x_i} = 0} $$ then $$\sum\limits_{i = 1}^{10} {{x_i}} $$ is
A.
0
B.
10
C.
5
D.
None of these
Answer :
10
Solution :
$$0 \leqslant {\cos ^{ - 1}}x \leqslant \pi .$$ Hence, from the question, $${\cos^{ - 1}}{x_i} = 0$$ for all $$i.$$
$$\therefore {x_i} = 1$$ for all $$i.$$
Releted MCQ Question on Trigonometry >> Inverse Trigonometry Function
Releted Question 1
The value of $$\tan \left[ {{{\cos }^{ - 1}}\left( {\frac{4}{5}} \right) + {{\tan }^{ - 1}}\left( {\frac{2}{3}} \right)} \right]$$ is
If we consider only the principle values of the inverse trigonometric functions then the value of $$\tan \left( {{{\cos }^{ - 1}}\frac{1}{{5\sqrt 2 }} - {{\sin }^{ - 1}}\frac{4}{{\sqrt {17} }}} \right)$$ is