题目
设 z = (u)/(x+y)，而 u = e^xy，则 (partial z)/(partial y) = ()A. (xe^xy)/(x+y)B. -(xe^xy)/((x+y)^2)C. ((x^2+xy-1)e^xy)/((x+y)^2)D. ((x+y-1)e^xy)/((x+y)^2)
设 $z = \frac{u}{x+y}$，而 $u = e^{xy}$，则 $\frac{\partial z}{\partial y} = ()$
A. $\frac{xe^{xy}}{x+y}$
B. $-\frac{xe^{xy}}{(x+y)^2}$
C. $\frac{(x^2+xy-1)e^{xy}}{(x+y)^2}$
D. $\frac{(x+y-1)e^{xy}}{(x+y)^2}$
题目解答
答案
C. $\frac{(x^2+xy-1)e^{xy}}{(x+y)^2}$