Limit Evaluation 1104Ec
1. **State the problem:**
Find the limits:
$$\lim_{x \to 5} (3x^2 - 1)$$
and
$$\lim_{x \to -2} (3x^3 + x^2 - 1)$$
2. **Recall the limit theorem for polynomials:**
For any polynomial function $f(x)$, the limit as $x$ approaches a value $a$ is simply $f(a)$ because polynomials are continuous everywhere.
3. **Evaluate the first limit:**
Substitute $x=5$ into $3x^2 - 1$:
$$3(5)^2 - 1 = 3 \times 25 - 1 = 75 - 1 = 74$$
4. **Evaluate the second limit:**
Substitute $x=-2$ into $3x^3 + x^2 - 1$:
$$3(-2)^3 + (-2)^2 - 1 = 3(-8) + 4 - 1 = -24 + 4 - 1 = -21$$
5. **Summary:**
$$\lim_{x \to 5} (3x^2 - 1) = 74$$
$$\lim_{x \to -2} (3x^3 + x^2 - 1) = -21$$
These results are confirmed by the continuity of polynomial functions and can be verified by a table of values approaching the limit points.