Inverse Trigonometric Functions Question 100

Question: What is the value of $ {{\sec }^{2}}{{\tan }^{-1}}( \frac{5}{11} )? $

Options:

A) $ 121/96 $

B) $ 211/921 $

C) $ 146/121 $

D) $ 267/121 $

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Answer:

Correct Answer: C

Let $ {{\sec }^{2}}( {{\tan }^{-1}}( \frac{5}{11} ) ) $

$ =1+{{\tan }^{2}}( {{\tan }^{-1}}( \frac{5}{11} ) )( \because {{\sec }^{2}}\theta -{{\tan }^{2}}\theta =1 ) $

$ =1+{{[ \tan ( {{\tan }^{-1}}( \frac{5}{11} ) ) ]}^{2}}=1+{{( \frac{5}{11} )}^{2}} $

$ =1+\frac{25}{121}=\frac{146}{121} $