Definite Integration Question 397

Question: $ \int_0^{\pi /3}{\cos 3xdx=} $

[SCRA 1980]

Options:

A) $ \pi $

B) 0

C) $ \frac{\pi }{2} $

D) $ \frac{\pi }{4} $

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Answer:

Correct Answer: B

Solution:

Required value is $ [ \frac{\sin 3x}{3} ]_0^{\pi /3}=0 $ .