A.2
B.2g′(a)
C.2ag′(a)
D.2bg′(a)
[单选题]A.2B.2g′(a)C.2ag′(a)D.2bg′(a)
[单选题]A.B.C.D.
[判断题]A.对B.错
[单选题]A.20B.200C.400D.416
[单选题]A.1B.2C.3D.4
[单选题]A.变长B.变短C.不变D.不能确定