问题
单项选择题
设f(x，y)在(0，0)处连续，[*]，则( )
A．f(x，y)在(0，0)处不可偏导
B．f(x，y)在(0，0)处可偏导但不可微
C．f'x(0，0)=f'y(0，0)=4且f(x，y)在(0，0)处可微分
D．f'x(0，0)=f'y(0，0)=0且f(x，y)在(0，0)处可微分
答案
参考答案：D,I,AC,G,AI,AH,C,B0,BA,BE,A0,AI,AI,C,C,E,A0,AF,G,F,I,AC,G,AI,AH,C,B0,BA,BE,A0,AI,AI,D,B,A0,AF,G,I,AC,G,AI,AH,C,B0,BA,BE,A0,AI,AI,D,C,A0,AF,G,BD,BE,I,AC,G,AI,AH,C,B0,BA,BE,A0,AI,AI,F,A,A0,AF,G,F,BD,BE,F,AI,BA,B,BD,AI,BA,B,F,AI,BA,B,BE,AI,BA,B,D