∫(0->1) x^2/(1+x) dx
=∫(0->1) (x^2-1 +1)/(1+x) dx
=∫(0->1) (x-1) dx +∫(0->1) 1/(1+x) dx
=(x^2/2 -x)|(0->1) +ln(x+1)|(0->1)
=(1/2-1) +(ln2-ln1)
=ln2 -1/2