?
The numerical value of $$\left( {\frac{1}{{\cos \theta }} + \frac{1}{{\cot \theta }}} \right)$$ $$\left( {\frac{1}{{\cos \theta }} - \frac{1}{{\cot \theta }}} \right)$$ is?
Answer & Solution
Correct Answer:
Option
C
$$\eqalign{
& \left( {\frac{1}{{\cos \theta }} + \frac{1}{{\cot \theta }}} \right){\text{ }}\left( {\frac{1}{{\cos \theta }} - \frac{1}{{\cot \theta }}} \right) \cr
& = \left( {\sec \theta + \tan \theta } \right)\left( {\sec \theta - \tan \theta } \right) \cr
& = {\sec ^2}\theta - {\tan ^2}\theta \left[ {1 + {{\tan }^2}\theta = {{\sec }^2}\theta } \right] \cr
& = 1 \cr} $$
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