1、y=(x² -3x)/(x+1)那么y'=[(x²-3x)' *(x+1) - (x²-3x)*(x+1)'] / (x+1)²显然(x²-3x)'=2x-3,(x+1)'=1,所以y'= [(2x-3)*(x+1) -(x²-3x)] / (x+1)²= (x²-4x-3)/(x+1)²2...