A.f″(x^2y)
B.f′(x^2y)+x^2f″(x^2y)
C.2x[f′(x^2y)+yf″(x^2y)]
D.2x[f′(x^2y)+x^2yf″(x^2y)]
[单选题]A.3.4B.3.OC.3.8D.3.2
[单选题]A.保持功能B.置“0”功能C.置“1”功能D.计数功能
[单选题]A.状态1B.状态2C.状态3D.状态4
[单选题]A.状态1B.状态2C.状态3D.状态4
[单选题]A.保持功能B.置“0”功能C.置“1”功能D.计数功能
[单选题]A.240B.237.5C.228D.213
[单选题]A.4B.5C.6D.7