Chapter 8.7, Problem 2QC

Using one computer algebra system, it was found that ${\displaystyle \int \sin x\cos xdx}=\frac{1}{2}{\sin }^{2}x+C$; using another computer algebra system, it was found that ${\displaystyle \int \sin x\cos xdx}=-\frac{1}{2}{\cos }^{2}x+C$. Reconcile the two answers.