If f(x)=xsin(1/x)f(x) = x \sin(1/x)f(x)=xsin(1/x) for x≠0x \neq 0x=0, what is the derivative f′(x)f'(x)f′(x)?
sin(1/x)−(1/x)cos(1/x)\sin(1/x) - (1/x)\cos(1/x)sin(1/x)−(1/x)cos(1/x)
sin(1/x)+cos(1/x)\sin(1/x) + \cos(1/x)sin(1/x)+cos(1/x)
cos(1/x)\cos(1/x)cos(1/x)
000