diff(y(x),x) = 1/(2*x+1)*(-2*y(x)-2*ln(2*x+1)-2+2*x*y(x)^3+y(x)^3+6*y(x)^2*ln(2*x+1)*x+3*y(x)^2*ln(2*x+1)+6*y(x)*ln(2*x+1)^2*x+3*y(x)*ln(2*x+1)^2+2*ln(2*x+1)^3*x+ln(2*x+1)^3)/(y(x)+ln(2*x+1)+1)