Question

The value of $9{\tan }^2\theta -9{\sec }^2\theta$ is

• A. $1$
• B. $0$
• C. $9$
• D. $-9$

Answer 1

Answer: (D)

$-9$

The value of $9{\tan }^2\theta -9{\sec }^2\theta$ is

$=9({\tan }^2\theta -{\sec }^2\theta )$

$=9({\sec }^2\theta -1-{\sec }^2\theta )$ ....$[$ Since ${\tan }^2\theta ={\sec }^2\theta -1]$

$=9(-1)$

$=-9$

Hence, option D is correct.