This could be very obvious and I am just not understanding very well.
I'm a little bit confused and can't seem to find the answer I am looking for even though it is probably simple. Looking online I can see plenty of examples of of extending (not sure this is the right term) a function to the interval $[-L,0]$ but not similar to my example below:
Say for example:
I consider the function $ f(x) = x^4$ in $[0,L]$ and am then asked to determine the even and odd expansions of $f(x)$ in $[-2L,2L]$.
How would I go about doing this compared to the interval $[-L,L]$? This example then leads into constructing sine and cosine fourier series in the interval $[-L,L]$ but I think I can do this part.
Apologies if my question is worded poorly and if you can help me work through this example it would be appreciated.