先将式子通分,得原式= lim x→0 ax?(1?a2x2)ln(1+ax) x2 = lim x→0 a+2a2xln(1+ax)? a?a3x2 1+ax 2x ( 0 0 型,运用洛必达法则);= lim x→0 a2x+2a2xln(1+ax) 2x ;= lim x→0 a2 2 + lim x→0 a2ln(1+ax);(极限的和运算)= a2 2 .