SSC CGL 2019 PYQ — Question 69

Concept

Understanding

Application

Fair calculation

Tan(90 – θ) = cot θ and

Sec²θ – tan²θ = 1

Apply these formulas and put the values.

Sec²29° – cot²61° + sin²60° + cosec²30°

⇒ sec²29°– cot²(90° - 29°) + (√3/2)² + 2²

⇒ sec²29° – tan²29° + 3/4 + 4

⇒ 1 + 3/4 + 4 = 23/4

1 + 3/4 + 4

⇒ (4 + 3 + 16)/4

⇒ 23/4