SSC CGL 2024 PYQ — Question 54

SSC CGL - 18 Sep 2024 - Shift 3 • Quantitative Aptitude • Q54

What is the value of 9sin226°+9sin264°+3632−7cos232°−7cos258°\sqrt{9sin^2 26°+9sin^2 64°+36\over 32-7cos^2 32°-7cos^2 58°}?

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. 3553\sqrt5\over5.

9sin226°+9sin264°+3632−7cos232°−7cos258°\sqrt{9sin^2 26°+9sin^2 64°+36\over 32-7cos^2 32°-7cos^2 58°}

=9sin226°+9sin2(90°−26°)+3632−7cos2(90°−58°)−7cos258°=\sqrt{9sin^2 26°+9sin^2 (90°-26°)+36\over 32-7cos^2 (90°-58°)-7cos^2 58°}

=9sin226°+9cos226°+3632−7sin258°−7cos258°=\sqrt{9sin^2 26°+9cos^2 26°+36\over 32-7sin^2 58°-7cos^2 58°}

=9(sin226°+cos226°)+3632−7(sin258°+cos258°)=\sqrt{9(sin^2 26°+cos^2 26°)+36\over 32-7(sin^2 58°+cos^2 58°)}

=9+3632−7=\sqrt{9+36\over 32-7}   [∵ sin2θ + cos2θ =1]

=4525=\sqrt{45\over 25}

= 3553\sqrt5\over5