Can it compute y=sin x?
For a vanilla MLP, you'd need to add in a few previous values (ie you'd predict x_{t+1} = f(x_t, ..., x_{t-N}), where f is your neural network and N is some fixed integer).
Check this out: https://www.desmos.com/calculator/rfaqogkbmy
Try changing f(x) to "sin(x)" or whatever you like (e.g. sin(10x) may be more interesting). Then drag the sliders for w (how step-like the purple pieces are) and n (how many pieces to add together). The function f(x) is red, and the approximation is blue.