Q. If $I_{n} = \int_{0}^{\frac{\pi}{4}}{\tan^{n}{\theta\ d\theta}}$, then $I_{8} + I_{6}$ is equal to

A) $\frac{1}{7}$
B) $\frac{1}{4}$
C) $\frac{1}{5}$
D) $\frac{1}{6}$
Explanation

(a)
$I_{8} + I_{6} = \int_{0}^{\frac{\pi}{4}}{\tan^{8}{\theta\ d\theta}} + \int_{0}^{\frac{\pi}{4}}{\tan^{6}{\theta\ d\theta}}$
$= \int_{0}^{\frac{\pi}{4}}{\sec^{2}\theta}\tan^{6}\theta d\theta$
$= \left\lbrack \frac{\tan^{7}\theta}{7} \right\rbrack_{0}^{\frac{\pi}{4}} = \frac{1}{7}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

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