∫2-x^2/1+x^2dx=

∫ x/(1+X^2)dx= ∫(x+1/x)^2dx=? ∫(1+x)/(X^2)dx=∫ [(1+x)/(X^2)]dx得什么? ∫[dx/(e^x(1+e^2x)]dx ∫1+2x/x(1+x)*dx∫1+2x/x(1+x) * dx ∫(x-1)^2dx, ∫x^1/2dx ∫x[x/[(2a-x)]^(1/2)dx=? 1/(x+x^2)dx ∫dx/x^2(1-x^2) ∫dx/x^2(1+x^2) ∫X^2/1-x^2 dx. ∫X^2/1-x^2 dx. ∫1/x^2+x+1dx ∫1/(x^2+x+1)dx ∫ (x+arctanx)/(1+x^2) dx ∫（x^2+1/x^4)dx ∫2 -1|x²-x|dx