SSC CGL 2020 PYQ — Question 51

SSC CGL - 4th March 2020 Shift 3 • Quantitative Aptitude • Q51

If Secθ + tanθ = p, 0o < θ < 90o, then (p2 - 1)/(p2 + 1) is equal to:

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e Sinθ.

Understanding/Application

Secθ + tanθ = p

sq. both sides -

(Secθ + tanθ)2 = p2 .....(1

(p2 - 1)/(p2 + 1)

{(Secθ + tanθ)2 - 1}/{(Secθ + tanθ) + 1}

(Sec2θ + tan2θ + 2Secθtanθ - 1)/(Sec2θ + tan2θ + 2Secθtanθ + 1)

{(Sec2θ - 1) + tan2θ + 2Secθtanθ }/{ Sec2θ + 2Secθtanθ + (tan2θ + 1)} 

(2tan2θ + 2Secθtanθ)/(2Sec2θ + 2Secθtanθ)

(tan2θ + Secθtanθ)/(Sec2θ + Secθtanθ )

{tanθ(1 + Secθ)}/{Secθ(1 + tanθ)}

(tanθ/Secθ)

Sinθ