题目
设z=e^-xsin(x)/(y)，则(partial^2 z)/(partial x partial y)在点(2,(1)/(pi))处的值为(）.A. (pi)/(e^2);B. (pi^2)/(e^2);C. (pi^2)/(e);D. (pi)/(e).
设$z=e^{-x}\sin\frac{x}{y}$，则$\frac{\partial^2 z}{\partial x \partial y}$在点$(2,\frac{1}{\pi})$处的值为(）.
A. $\frac{\pi}{e^2}$;
B. $\frac{\pi^2}{e^2}$;
C. $\frac{\pi^2}{e}$;
D. $\frac{\pi}{e}$.
题目解答
答案
B. $\frac{\pi^2}{e^2}$;