Question

What is the frequency of `f(theta)= sin 12 t - cos 84 t`?

Answer 1

The frequency is `=1.91`

Explanation:

The period of the sum of 2 periodic functions is the LCM of their periods

The period of `sin12t` is `=(2pi)/12=pi/6`

The period of `cos84t` is `=(2pi)/84=pi/42`

The LCM of `pi/6` and `pi/42` is `=(7pi)/42=pi/6`

The frequency is

`f=1/T=1/(pi/6)=6/pi=1.91`