满意答案chuyi0480LV122017-04-23 解:对数有意义,x>0令f(x)=lnx-ex,(x>0)f'(x)=1/x -e阳令f'(x)≥0来自,1/x-e≥0,1/x≥e0<x≤1/e,f(x)在(0,1/e]上单调递增,在[1/e,+∞)上单调递减x=1/e时,f(x)取得最大值f(x)max=f(1/e)=ln(1/e) -e·(1/e)=-1-1=-2<0f(x)恒<0,lnx恒<ex方程lnx=ex无解01