原式=∫dx/((x+1)^2+2)^2
x+1=√2tanu sin2u=2√2(x+1)/(x^2+2x+3)
=∫√2(secu)^2du/[4(secu)^4]
=(√2/8)∫(1+cos2u)du
=√2u/8+√2sin2u/16
=(√2/8)arctan[(x+1)/√2]+(x+1)/[4(x^2+2x+3)]+C
原式=∫dx/((x+1)^2+2)^2
x+1=√2tanu sin2u=2√2(x+1)/(x^2+2x+3)
=∫√2(secu)^2du/[4(secu)^4]
=(√2/8)∫(1+cos2u)du
=√2u/8+√2sin2u/16
=(√2/8)arctan[(x+1)/√2]+(x+1)/[4(x^2+2x+3)]+C