How can i tell a period of a function involving sin and cos

[th3plan]

Homework Statement

Ok so we started Fourier Analysis in circuits. How can i tell the Period of a function that's let's say sin(2t)+3cos(5t) something like that . Any help or url's that have information on this

 

[Mark44]

For your example, the period of sin(2t) is pi and the period of cos(5t) is 0.4pi. The smallest interval that is a multiple of both pi and 0.4 pi is 2pi, so that would be the period of the sum of the two functions.