Question

What is the period of `f(t)=sin( t / 15 )+ cos( (t)/21 )`?

Answer 1

`210pi`

Explanation:

Period of sin (t/15) --> `30 pi`
Period of cos (t/21) = `42pi`
Find the least common multiple

`30pi` x (7) ---> `210pi`
`42pi` x (5) ---> `210pi`

Period of f(t) ---> `210pi`