I evaluate the following integral with pen and paper:
$$\int y'(x) \cdot (y(x) +1)^2 \cdot dx$$
And I get to the following result:
$$\frac{(y(x) + 1)^3}{3}+C$$
However, after that I went to WolframAlpha to check if my answer was right, I got the following result:
Which is pretty much what I got, but where does $\dots +y(x)^2+y(x)$ come from?
I do not understand that. I would appreciate it if somebody explains that to me.