SSC CGL 2024 PYQ — Question 55

SSC CGL - 18 Sep 2024 - Shift 3 • Quantitative Aptitude • Q55

The given expression is equivalent to:

secθ+1secθ−1 + secθ−1secθ+1\sqrt{secθ+1\over secθ-1}\ +\ \sqrt{secθ-1\over secθ+1}

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. 2 cosecθ.

secθ+1secθ−1 + secθ−1secθ+1\sqrt{secθ+1\over secθ-1}\ +\ \sqrt{secθ-1\over secθ+1}

=secθ+1secθ−1+secθ−1secθ+1=\frac{\sqrt{sec\theta+1}}{\sqrt{sec\theta-1}}+\frac{\sqrt{sec\theta-1}}{\sqrt{sec\theta+1}}

=(secθ+1)+(secθ−1)sec2θ−1=\frac{(sec\theta+1)+(sec\theta-1)}{\sqrt{sec^2\theta-1}}

=2secθtanθ=\frac{2sec\theta}{tan\theta}   [∵tanθ=sec2θ−1][ ∵ tan\theta=\sqrt{sec^2\theta-1}]

= 2 × (1/cosθ) × (cosθ/sinθ)   [∵ secθ = 1/cosθ and tanθ = sinθ/cosθ]

= 2/sinθ   [∵ sinθ = 1/cosecθ]

= 2cosecθ