Find the derivative of f(x)=excos(x)f(x) = e^{x} \cos(x)f(x)=excos(x).
ex(cosx−sinx)e^x(\cos x - \sin x)ex(cosx−sinx)
ex(cosx+sinx)e^x(\cos x + \sin x)ex(cosx+sinx)
−exsinx-e^x \sin x−exsinx
excosx−exsinxe^x \cos x - e^x \sin xexcosx−exsinx