# What is the period of f(t)=sin( t / 40 )+ cos( (t)/ 4) ?

$8 o \pi$
Period of $\sin \left(\frac{t}{40}\right)$ --> $40 \cdot \left(2 \pi\right)$ --> $80 \pi$
Period of $\cos \left(\frac{t}{4}\right)$ --> $4 \cdot \left(2 \pi\right)$ --> $8 \pi$.
Common period: $80 \pi$