What is the frequency of f(θ)=sin3tcos21t?

1 Answer
Apr 18, 2016

32π

Explanation:

Noting that sin(t) and cos(t) both have a period of 2π, we can say that the period of sin(3t)cos(21t) will be 2πgcd(3,21)=2π3, which is the least positive value such that both terms will finish a period simultaneously.

We know that the frequency is the inverse of the period, that is, given period P and frequency f, we have f=1P.

In this case, as we have the period as 2π3, that gives us a frequency of 32π