$x(t)=x(t+T)=a_0+{\displaystyle \underset{n=1}{\overset{}{}}}{a}_{n}cos(n{}_{0}t)+b_{n}sin(n{}_{0}t)$

$a_0=\frac{1}{T}{\displaystyle \underset{0}{\overset{T}{}}}f(t)dt$

$a_n=\frac{2}{T}{\displaystyle \underset{0}{\overset{T}{}}}f(t)cos(n{}_{0}t)dt$

$b_n=\frac{2}{T}{\displaystyle \underset{0}{\overset{T}{}}}f(t)sin(n{}_{0}t)dt$

all the $a_n$ coefficients are zero. This means you just need to find the first five $b_n$ coefficients $b_1,b_2,b_3,b_4,$ and $b_5.$ simplified as much as possible$).$ period of the waveform, and they should be well$-$labeled and clear.

Submit all your work as one well$-$organized PDF$.$

Note that the waveform has a period $T=4[$seconds$]$