Question

What is the period of f(x) = Sinx. Cos3x ?

• A. $2\pi$
• B. $1$
• C. $2$
• D. $\frac{\pi }{2}$

Answer 1

The correct option is A

$2\pi$

We know, that period of f(x) . g(x) will be equal to the LCM of periods of f(x) & g(x)

Here, the period of Sinx = $2\pi$

And the period of Cos 3x = $\frac{2\pi }{3}$

And the LCM of both the periods will be = $2\pi$

Hence the period of f(x) = Sinx . cos (3x) is $2\pi$.