Verify Integral is correct

Question

How do I verify if this is correct? ∫xsin x dx = -xcosx+sinx+C

Answer 1

Differentiate the result of the integration, and verify it gives the integrand.

d/dx[-x cos(x) + sin(c) + c] = -[cos(x) - x sin(x)] + cos(x) = x sin(x)