Question

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

• A. 2π
• B. 1
• C. 2
• D. π/2

Answer 1

The correct option is A

2π

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 $2\pi$.