What is the derivative of the function f (x) = SiNx / x? The answer is xcosx SiNx / x ^ 2

What is the derivative of the function f (x) = SiNx / x? The answer is xcosx SiNx / x ^ 2

f'(x)=[(sinx)'*x-sinx*x']/x²
=(xcosx-sinx)/x²