Question

What is the frequency of `f(theta)= sin 18 t - cos 4 t`?

Answer 1

`pi`

Explanation:

Period of sin (18t) --> `(2pi)/18 = pi/9`
Period of cos 4t --> `(2pi)/4 = pi/2`
Period of f(t) --> least common multiple of (pi/9) and (pi/2)
`pi/9` ...x (9) --> `pi`
`pi/2` ...x (2) -->`pi`

Period of f(t) --> `pi`