A:﹣2b3+3ab2+4a2b+a3
B:a3+4a2b+3ab2﹣2b3
C:4a2b+3ab2﹣2b3+a3
D:4a2b+3ab2+a3﹣2b3
—_______?
—Pretty good! How about you?
对于R上可导的任意函数f(x),若满足x-1f'x=0,则必有( )