SSC CGL 2025 PYQ — Question 59

SSC CGL - 22 Sep 2025 - Shift 1 • Quantitative Aptitude • Q59

If sin A = 513\frac{5}{13}, and A lies in the 2nd quadrant, then find the value of sin A × sec A.

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Correct answer: B

Explanation

The correct answer is option 2 i.e. −512-\frac{5}{12}.

sin⁡A=513\sin A = \frac{5}{13}

⇒ sin⁡2A=25169\sin^2 A = \frac{25}{169}

In the 2nd quadrant, cos A is negative.

sin⁡2A+cos⁡2A=1\sin^2 A + \cos^2 A = 1

⇒ 25169+cos⁡2A=1\frac{25}{169} + \cos^2 A = 1

⇒ cos⁡2A=1−25169=144169\cos^2 A = 1 - \frac{25}{169} = \frac{144}{169}

⇒ cos⁡A=−144169=−1213\cos A = -\sqrt{\frac{144}{169}} = -\frac{12}{13}

⇒ sec⁡A=1cos⁡A=1−12/13=−1312\sec A = \frac{1}{\cos A} = \frac{1}{-12/13} = -\frac{13}{12}

⇒ sin⁡A×sec⁡A=513×(−1312)=−512\sin A \times \sec A = \frac{5}{13} \times \left( -\frac{13}{12} \right) = -\frac{5}{12}