1. Problem with Integral I got stuck on the following Integal and can't find the mistake: [tex]Integral(x/(x-1))[/tex] let U' = x and V = (x-1)^(-1) and U= 0.5x^2 V' = 1/(x-1)^2 so: [tex]x^2/(2(x-1))-1/2Integral(x^2/(x-1)^2[/tex] algebraic division: [tex]x^2 : (x^2 -2x + 1) = 1- 1/(x-1)^2 + 1/(x-1)^2[/tex] substituting back into equation gives: [tex] 1/2 [x^2/(x-1) - x - ln (x-1)^2 x 1/(x-1)] = (x+1)/(2(x-1)) + ln(x-1)[/tex] but the result is supposed to be: [tex]x + ln(x-1)[/tex] 2. Substitution in ODE [tex]xydy/dx + (x^2 + y^2 +x) = 0 [/tex] I have tried to substitute z = xy and also z = x^2 + y^2, but that didn't work. Any other ideas? Thank you!