已知函数f(x)=
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.
(1)求f(x)的单调区间;
(2)若a>0,x
1+x
2>0,x
2+x
3>0,x
3+x
1>0,|x
i|>
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124106453602371/SYS201310251241064536023019_ST/1.png)
(i=1,2,3).求证:f(x
1)+f(x
2)+f(x
3)>2
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124106453602371/SYS201310251241064536023019_ST/2.png)
.
考点分析:
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