Question: User: Lim $x-(-1)$ $x^3+1/x+1$
1. **State the problem:** We need to find the limit of the expression $$x - (-1) \cdot \frac{x^3 + 1}{x + 1}$$ as $x$ approaches $-1$.
2. **Rewrite the expression:** The expression can be written as $$x + \frac{x^3 + 1}{x + 1}$$ because $-(-1) = +1$.
3. **Factor the numerator:** Note that $x^3 + 1$ is a sum of cubes, which factors as $$x^3 + 1 = (x + 1)(x^2 - x + 1)$$.
4. **Simplify the fraction:** Substitute the factorization into the fraction:
$$\frac{x^3 + 1}{x + 1} = \frac{(x + 1)(x^2 - x + 1)}{x + 1}$$
Cancel the common factor $x + 1$:
$$\frac{\cancel{(x + 1)}(x^2 - x + 1)}{\cancel{x + 1}} = x^2 - x + 1$$
5. **Rewrite the original expression:** Now the expression is
$$x + x^2 - x + 1 = x^2 + 1$$
6. **Evaluate the limit:** Substitute $x = -1$ into $x^2 + 1$:
$$(-1)^2 + 1 = 1 + 1 = 2$$
**Final answer:**
$$\lim_{x \to -1} \left(x - (-1) \cdot \frac{x^3 + 1}{x + 1}\right) = 2$$