f'(x)=a*e^x+(ax+1)*e^x=(ax+a+1)*e^x 又因为e^x>0
令f'(x)=0,则x=-(a+1)/a
a>0,当x属于(负无穷,-(a+1)/a),f'(x)0,f(x)单调递增
当x属于(-(a+1)/a,正无穷),f'(x)
f'(x)=a*e^x+(ax+1)*e^x=(ax+a+1)*e^x 又因为e^x>0
令f'(x)=0,则x=-(a+1)/a
a>0,当x属于(负无穷,-(a+1)/a),f'(x)0,f(x)单调递增
当x属于(-(a+1)/a,正无穷),f'(x)