SSC CGL 2021 PYQ — Question 53

SSC CGL - 20 Aug 2021 - Shift 3 • Quantitative Aptitude • Q53

The value of sec4 θ\theta(1 - sin4θ\theta) - 2tan2θ\theta is:

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. 1

Here it is given that,

 = sec4θ\theta(1 - sin4θ\theta) - 2tan2θ\theta  

= 1/cos4θ\theta( 1 - (sin2θ\theta)2) - 2 × sin2θ\theta/cos2θ\theta

= 1/cos2θ\theta(1 - sin2θ\theta) × (1 + sin2θ\theta)(1 - sin2θ\theta) -  2 × sin2θ\theta/cos2θ\theta

=  (1 + sin2θ\theta)/ cos2θ\theta  -   2 × sin2θ\theta/cos2θ\theta

= ( 1 + sin2θ\theta - 2sin2θ\theta)/ cos2θ\theta

=  cos2θ\theta/ cos2θ\theta

= 1.