Differentiability - uni maths

let f(x) =
{(x^2) sin(1/x) x=/=0
0, x=0}

Show that f'(x) exists at every x, but f' is not continuous at x=0

Any help appreciated :)

f '(x) = -cos(1/x) + 2x*sin(1/x)

Note that at x = 0, we get 1/0 in the sine and cosine arguments and this is not possible.