导数判别法:f'(x)=ae^x-1令f'(x)>0则解得x>ln(1\a),此为单调增区间令f'(x)<0则解得xf'(x)=ae^x-1>0ae^x>1e^x>1\a两边对e求对数x>ln(1\a)
f'(x)=ae^x-1=0 求极值点:得:e^x=1/a如果a<=0, 则f'(x)<=-1, 函数单调减如果a>0, 由e^x=1/a得:极值点即为:x=ln(1/a)=-lna, 当x<-lna时,单调减;当x>-lna时,单调增