Construct the first three Fourier approximations to the square wave function:
{1, -T < x < 0
f(x) = -1, 0 < x < T
F1(x) = (4/T)sin(xπ)
F2(x) = (4/T)sin(3xπ)/(3π)
F3(x) = (4/T)sin(5xπ)/(5π)
Using a calculator, graph the function and the first three Fourier approximations to see how the approximation matches the function f(x).