even function

Which one of the following options is the correct Fourier series of the periodic function $f(x)$ described below: $$ f(x)=\left\{\begin{array}{cl} 0 & \text { if }-2

The following function is defined over the interval [-L, L]: f(x) = px^4 + qx^5. If it is expressed as a Fourier series, f(x) = a_0 + \sum_{n=1}^{\infty} \{a_n \sin(\frac{\pi x}{L}...

The function $$f\left( x \right) = {e^x}$$ is _________.