# What is the frequency of f(theta)= sin 12 t - cos 18 t ?

Sep 11, 2016

$\pi$

#### Explanation:

Frequency of sin (12t) --> $\frac{2 \pi}{12} = \frac{\pi}{6}$
Frequency of cos (18t) -->$\frac{2 \pi}{18} = \frac{\pi}{9}$
Least common multiple of $\frac{\pi}{6} \mathmr{and} \frac{\pi}{9}$ is $\pi$
$\left(\frac{\pi}{6}\right)$ ... x (6) ...--> $\pi$
$\left(\frac{\pi}{9}\right)$ .... x (9) ... --> $\pi$
Frequency of f(t) is $\pi$