# Radical cosx * Sinx dx. U=? (Don’t integrate)

I assume you mean $\sqrt{\cos} \left(x\right) \cdot \sin \left(x\right) \setminus \mathrm{dx}$ because if both are under the radical the result is nonelementary.
If I have it right use $u = \cos \left(x\right)$ with $\sin \left(x\right) \setminus \mathrm{dx} = - \mathrm{du}$ and the rest works out nicely.