1、f(x)=x^2+2x-2ln(1+x)
f'(x)=2x+2-2/(1+x)
=2(x+1-1/(1+x)
=2(x^2+2x)/(x+1)
=2x(x+2)/(x+1)
单增:f'(x)>0
2x(x+2)/(x+1)>0
单增区间:-2