Inverse Trigonometric Functions Question 166

Question: $ {{\sec }^{2}}({{\tan }^{-1}}2)+cose{c^{2}}({{\cot }^{-1}}3)= $

[EAMCET 2001]

Options:

A) 5

B) 13

C) 15

D) 6

Show Answer

Answer:

Correct Answer: C

Solution:

Let $ {{\tan }^{-1}}2=\alpha \Rightarrow \tan \alpha =2 $ and $ {{\cot }^{-1}}3=\beta \Rightarrow \cot \beta =3 $

$ {{\sec }^{2}}({{\tan }^{-1}}2)+cose{c^{2}}({{\cot }^{-1}}3) $ = $ {{\sec }^{2}}\alpha +cose{c^{2}}\alpha $ = $ 1+{{\tan }^{2}}\alpha +1+{{\cot }^{2}}\alpha $ = $ 2+{{(2)}^{2}}+{{(3)}^{2}}=15 $ .