# How do I understand the result of symbolic integrals

So now I know how to integrate, but when I type in

```
sage: deriv=diff((exp(x)-1)/x,x); deriv
e^x/x - (e^x - 1)/x^2
sage: deriv.integrate(x)
-1/x + Ei(x) - gamma(-1, -x)
```

why don't I get back `(exp(x)-1)/x +C`

?