函数
在点A(1,0,1)处沿点A指向点B(3,-2,2)方向的方向导数为______.
参考答案:[*]
解析:[*]
– You look so happy!
– Jack says I am pretty. has ever told me that before.
A. Somebody B. Everybody C. Nobody
心包压塞的征像是什么?