This form can also be expanded into a complex exponential (CE) Fourier series of the form: $$ f(x) = \sum_{n=-\infty}^{+\infty} C_n e^{inx} $$

and vice versa. Here we define, for convenience: $$ B_n := 0 $$

**(a)**Prove that the SC Fourier coefficients ##A_j## and ##B_j## for non-negative integer ## j = 0,1,2,3...## are related to the CE Fourier coefficients ##C_n## by: $$ A_j = C_j + C_{-j} ; \\ B_j = i(C_j - C_{-j}) ; \\ for: j = 0,1,2,3... $$

**Hint:**All you need here is Euler: ## e^{i\gamma} = cos(\gamma) + isin(\gamma) ## or ## cos(\gamma) = (e^{i\gamma} + e^{-i\gamma})/2 ## or ## sin(\gamma) = (e^{i\gamma} - e^{-i\gamma})/(2i) ##

I plugged in the Euler formula to the CE Fourier series and evaluated the definite integral from -pi to pi, which equaled zero, soooo i'm not too sure what to do...