Find the cosine series for the function defined by $f(x)=2$, $0 \le x \lt 1$ and $f(x)=0$, $1 \le x \lt 2$.

Question

In class we only went over the series that are on an interval $x \in[-L,L]$ where $L$ is a positive real number. Here, we have $x \in [0,2]$, and I cannot do the transformation given in class where we would use $\frac{t}{\pi}=\frac{x}{L}$ since there is no $L$.

How would I approach this problem with such an interval?