Integral Calculus Question 297

Question: $ \int_{{}}^{{}}{\frac{dx}{4{{\cos }^{3}}2x-3\cos 2x}}= $

Options:

A) $ \frac{1}{3}\log [\sec 6x+\tan 6x]+c $

B) $ \frac{1}{6}\log [\sec 6x+\tan 6x]+c $

C) $ \log [\sec 6x+\tan 6x]+c $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

$ \int_{{}}^{{}}{\frac{dx}{4{{\cos }^{3}}2x-3\cos 2x}}=\int_{{}}^{{}}{\frac{dx}{\cos 6x}=\int_{{}}^{{}}{\sec 6xdx}} $ $ =\frac{1}{6}\log ,(\sec 6x+\tan 6x)+c. $