Trigonometric Identities Question 233

Question: The value of $ {{\tan }^{2}}\theta {{\sec }^{2}}\theta ({{\cot }^{2}}\theta -{{\cos }^{2}}\theta ) $ is

Options:

A) $ 0 $

B) $ 1 $

C) $ -1 $

D) $ \frac{1}{2} $

Show Answer

Answer:

Correct Answer: B

Solution:

$ {{\tan }^{2}}\theta sec^{2}\theta ({{\cot }^{2}}\theta -{{\cos }^{2}}\theta ) $ $ ={{\sec }^{2}}\theta ({{\tan }^{2}}\theta {{\cot }^{2}}\theta -{{\tan }^{2}}\theta {{\cos }^{2}}\theta ) $ $ ={{\sec }^{2}}\theta ( 1-\frac{{{\sin }^{2}}\theta }{{{\cos }^{2}}\theta }{{\cos }^{2}}\theta )={{\sec }^{2}}\theta (1-{{\sin }^{2}}\theta ) $ $ ={{\sec }^{2}}\theta .,{{\cos }^{2}}\theta =1 $