When integrating 2sin(x)cos(x), I used a simple u sub and got sin^2(x), no big deal. However when I pop this into wolfram, it results in (-1/2)cos(2x). This is the link Wolfram Mathematica Online Integrator
I take the derivative of what wolfram gives me and it certainly is not 2sin(x)cos(x). Can someone tell me what I did wrong please?