快 求学霸解答(最好写纸上拍了发来)QAQ
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/19 06:19:08
快 求学霸解答(最好写纸上拍了发来)QAQ
![](http://img.wesiedu.com/upload/0/5e/05e463364843b81e43babb3bb2e65781.jpg)
![](http://img.wesiedu.com/upload/9/89/989a32fdac7385b0a9b5be6998f85162.jpg)
![](http://img.wesiedu.com/upload/a/89/a899785b4e7f96367124d03cefd05f5e.jpg)
![](http://img.wesiedu.com/upload/c/90/c90455b69df820c953533dd0426a2e53.jpg)
![](http://img.wesiedu.com/upload/4/0f/40f3c89056f90251c2f576a587a30efe.jpg)
![](http://img.wesiedu.com/upload/0/5e/05e463364843b81e43babb3bb2e65781.jpg)
![](http://img.wesiedu.com/upload/9/89/989a32fdac7385b0a9b5be6998f85162.jpg)
![](http://img.wesiedu.com/upload/a/89/a899785b4e7f96367124d03cefd05f5e.jpg)
![](http://img.wesiedu.com/upload/c/90/c90455b69df820c953533dd0426a2e53.jpg)
![](http://img.wesiedu.com/upload/4/0f/40f3c89056f90251c2f576a587a30efe.jpg)
太多了分开来提问吧 不可能有人全解答的
我就解答一下33:(看看一道题就这么多字了)
1、∵e^x>0,f(x)>0
∴ax^2+x>0
∴ax(x+1/a)>0
解得x∈(0,-1/a)
2、求导f'(x)=(ax^2+x)'(e^x)+(e^x)'(ax^2+x)
=(2ax+1)(e^x)+(e^x)(ax^2+x)
=2axe^x+e^x+ax^2e^x+xe^x
=e^x(ax^2+x+2ax+1)
依题意,可知在区间[-1,1]上,f'(x)>0
∵e^x>0,∴令g(x)=ax^2+(2a+1)x+1>0
①a=0,则x+1>0,x>-1,符合题意
②a>0,则g(x)开口向上
对称轴-1-1/2a0
∵a>0,∴-a
我就解答一下33:(看看一道题就这么多字了)
1、∵e^x>0,f(x)>0
∴ax^2+x>0
∴ax(x+1/a)>0
解得x∈(0,-1/a)
2、求导f'(x)=(ax^2+x)'(e^x)+(e^x)'(ax^2+x)
=(2ax+1)(e^x)+(e^x)(ax^2+x)
=2axe^x+e^x+ax^2e^x+xe^x
=e^x(ax^2+x+2ax+1)
依题意,可知在区间[-1,1]上,f'(x)>0
∵e^x>0,∴令g(x)=ax^2+(2a+1)x+1>0
①a=0,则x+1>0,x>-1,符合题意
②a>0,则g(x)开口向上
对称轴-1-1/2a0
∵a>0,∴-a