If f(x,y)=e2x−yf(x,y) = e^{2x-y}f(x,y)=e2x−y, find the mixed partial derivative fxyf_{xy}fxy.
−2e2x−y-2 e^{2x-y}−2e2x−y
2e2x−y2 e^{2x-y}2e2x−y
−e2x−y-e^{2x-y}−e2x−y
−4e2x−y-4 e^{2x-y}−4e2x−y