What is the period of #f(t)=sin( t / 18 )+ cos( (t)/21 ) #?
The periods dor both sin kt and cos kt is
Here, the periods of the separate oscillations given by
For the compounded oscillation f(t), the period is given by
integers L and M. So,
See how it works.
Note that when this P is halved, the first term would change its sign..