SSC CGL 2023 PYQ — Question 71

SSC CGL - 19 July 2023 - Shift 1 • Quantitative Aptitude • Q71

If sinx−cosxsinx+cosx=25\frac{sinx-cosx}{sinx+cosx}=\frac{2}{5}, then the value of 1+cot2x1−cot2x\frac{1+cot^2x}{1-cot^2x}?

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. 1.45.

Given that

If sinx−cosxsinx+cosx=25\frac{sinx-cosx}{sinx+cosx}=\frac{2}{5},

Caculation

⇒ sinx(1−cotx)sinx(1+cotx)=25\frac{sinx(1-cotx)}{sinx(1+cotx)}=\frac{2}{5}

⇒ (1−cotx)(1+cotx)=25\frac{(1-cotx)}{(1+cotx)}=\frac{2}{5}

⇒ 5 - 5 cotx = 2 + 2 cotx

⇒ 7 cotx = 3

⇒ cotx = 3/7

Hence, the value 1+cot2x1−cot2x\frac{1+cot^2x}{1-cot^2x} = 1+9/491−9/49\frac{1+9/49}{1-9/49} = 58/40 = 1.45