问题
单项选择题
设z=f(x,v)，v=v(x，y)，f，v均有二阶偏导数，则
=（）。
A.A
B.B
C.C
D.D
答案
参考答案：C
解析：
[点评] 考察复合函数求高阶偏导数。
搜题请搜索小程序“爱下问搜题”
设z=f(x,v)，v=v(x，y)，f，v均有二阶偏导数，则=（）。
A.A
B.B
C.C
D.D
参考答案：C
解析：
[点评] 考察复合函数求高阶偏导数。
从方框中选择适当的动词并用其正确形式填空,完成句子.
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| 1. It doesn't _____ when you'll come back. 2. They _____ off their conversation when someone knocked at the door. 3. —You look unhappy, Tina. What's wrong? —I _____ my new watch on my way home. 4. He must _____ the fact that he is no longer young. 5. Mrs. Liu is _____ as one of the best teachers in the school. |