Limits Derivatives
1. **Problem:** Find the limit $\lim_{x \to -3} h(x)$ using the graph.
From the graph, at $x = -3$, $h(x) = 1$.
2. **Problem:** Find the right-hand limit $\lim_{x \to 2^+} h(x)$.
From the graph, as $x$ approaches 2 from the right, $h(x)$ approaches 2.
3. **Problem:** Find points of discontinuity of $f(x)$ from the given options.
Discontinuities occur where the function is not continuous. Based on the graph and options, the correct points are $-3,1,2$.
4. **Problem:** Calculate $\lim_{x \to 2} \sqrt[3]{\frac{5x + 6}{x}}$.
Substitute $x=2$:
$$\sqrt[3]{\frac{5(2) + 6}{2}} = \sqrt[3]{\frac{10 + 6}{2}} = \sqrt[3]{8} = 2$$
5. **Problem:** Calculate $\lim_{x \to -3} \frac{x^2 + 5x + 6}{2x + 6}$.
Factor numerator:
$$x^2 + 5x + 6 = (x+2)(x+3)$$
Denominator:
$$2x + 6 = 2(x+3)$$
Simplify:
$$\frac{(x+2)(x+3)}{2(x+3)} = \frac{x+2}{2}, x \neq -3$$
Substitute $x = -3$:
$$\frac{-3 + 2}{2} = \frac{-1}{2} = -\frac{1}{2}$$
6. **Problem:** Given
$$f(x) = \begin{cases} x^2 - 2x, & x \leq 3 \\ 2x - 1, & x > 3 \end{cases}$$
Find $\lim_{x \to 3^+} f(x)$.
For $x > 3$, use $2x - 1$:
$$\lim_{x \to 3^+} f(x) = 2(3) - 1 = 6 - 1 = 5$$
7. **Problem:** Given $f(x) = x^3 - 3x^2$, find $f'(2)$.
Derivative:
$$f'(x) = 3x^2 - 6x$$
Evaluate at $x=2$:
$$f'(2) = 3(2)^2 - 6(2) = 12 - 12 = 0$$
(Note: None of the options match 0, so likely a typo; closest is 2.)
8. **Problem:** Given $y = \frac{x^5 - 8x^3}{4x}$, find $\frac{dy}{dx}$.
Rewrite:
$$y = \frac{x^5}{4x} - \frac{8x^3}{4x} = \frac{x^4}{4} - 2x^2$$
Differentiate:
$$\frac{dy}{dx} = \frac{4x^3}{4} - 4x = x^3 - 4x$$
9. **Problem:** Given $f(x) = x^2 - 3x + 6$, find the tangent line at $(4,2)$.
Find $f'(x)$:
$$f'(x) = 2x - 3$$
Slope at $x=4$:
$$m = 2(4) - 3 = 8 - 3 = 5$$
Equation of tangent line:
$$y - 2 = 5(x - 4) \Rightarrow y = 5x - 20 + 2 = 5x - 18$$
None of the options match exactly; closest is $y = 7x + 3$ (likely a typo).
10. **Problem:** Given $f(x) = 3x^2 + 3x$, find points where the tangent slope is zero.
Derivative:
$$f'(x) = 6x + 3$$
Set slope zero:
$$6x + 3 = 0 \Rightarrow x = -\frac{1}{2}$$
Find $f(-\frac{1}{2})$:
$$3(-\frac{1}{2})^2 + 3(-\frac{1}{2}) = 3(\frac{1}{4}) - \frac{3}{2} = \frac{3}{4} - \frac{3}{2} = -\frac{3}{4}$$
Point is $(-\frac{1}{2}, -\frac{3}{4})$, not listed in options.
**Final answers:**
1) a) 1
2) c) 2
3) b) -3,1,2
4) c) 2
5) a) -1/2
6) b) 5
7) (closest) b) 2
8) d) $x^3 - 4x$
9) (none exact)
10) (none exact)