1.∫[1/(2x+1)^2]dx = (1/2)∫[1/(2x+1)^2]d(2x +1) = -(1/2)[1/(2x+1)] + C
2.∫xlnxdx = (1/2)∫lnxdx^2 = (1/2)(x^2)lnx - (1/2)∫xdx = (1/2)(x^2)lnx - (1/2)x^2 + C
3.∫[2,-1][(x+1)/√(x+2)]dx
=∫[2,1][(t-1)/√t]dt (t = x+2)
=∫[2,1][√t-(1/√t)]dt
= ...
余下的留给你,不行再给.