Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

Find value of \(\frac{3\;cos^2 37°\;-\;5\;+\;3 cos^2 53°}{tan^2 32°\;+\;4\;-\;cosec^2 58°}\) + sin 25° cos 65° + sin 65° cos 25°.

Options:

\(\frac{1}{3}\)

-\(\frac{1}{3}\)

1

\(\frac{2}{3}\)

Correct Answer:

\(\frac{1}{3}\)

Explanation:

If A + B = 90° , then cos2 A + cos2 B = 1

Now,

\(\frac{3 cos^2 37° - 5 + 3 cos^2 53°}{tan^2 32° + 4 - cosec^2 58°}\) + sin 25° cos 65° + sin 65° cos 25°

= \(\frac{3(cos^2 37°\;+\;cos^2 53°)\;-\;5}{tan^2 32°\;+\;4\;-\;sec^2 32°}\) + sin (25° + 65°)

= \(\frac{3\;-\;5}{4\;- (sec^2 32° - tan^2 32°)}\) + sin (25° + 65°)

= \(\frac{3\;-\;5}{4\;-\;1}\) + sin 90°

= - \(\frac{2}{3}\) + 1

\(\frac{1}{3}\)