1. **State the problem:** We need to find the derivative of the product function $h(x) = f(x) \cdot g(x)$ at $x=1$, $x=2$, and $x=3$. The graph of $f(x)$ has a sharp corner at $x=2$, and $g(x)$ is a straight line.
2. **Recall the product rule:** The derivative of a product of two functions is given by
$$h'(x) = f'(x)g(x) + f(x)g'(x).$$
3. **Find $f'(x)$ and $g'(x)$ at the points:**
- $f(x)$ is piecewise linear: from $(0,0)$ to $(2,2)$ and from $(2,2)$ to $(4,0)$.
- For $0 < x < 2$, slope $f'(x) = \frac{2-0}{2-0} = 1$.
- For $2 < x < 4$, slope $f'(x) = \frac{0-2}{4-2} = -1$.
- At $x=2$, $f'(2)$ does not exist due to the sharp corner.
- $g(x)$ is a straight line from approximately $(0,4)$ to $(4,0)$.
- Slope $g'(x) = \frac{0-4}{4-0} = -1$ everywhere.
4. **Evaluate $f(x)$ and $g(x)$ at $x=1,2,3$:**
- $f(1)$ lies on the first segment: $f(1) = 1$.
- $f(2) = 2$ (peak).
- $f(3)$ lies on the second segment: $f(3) = 1$.
- $g(1) = 4 - 1 = 3$ (since slope is -1 and intercept approx 4).
- $g(2) = 4 - 2 = 2$.
- $g(3) = 4 - 3 = 1$.
5. **Calculate $h'(x)$ at each point:**
**A. At $x=1$:**
$$h'(1) = f'(1)g(1) + f(1)g'(1) = (1)(3) + (1)(-1) = 3 - 1 = 2.$$
**B. At $x=2$:**
$f'(2)$ does not exist due to the sharp corner, so
$$h'(2) = \text{dne}.$$
**C. At $x=3$:**
$$h'(3) = f'(3)g(3) + f(3)g'(3) = (-1)(1) + (1)(-1) = -1 - 1 = -2.$$
**Final answers:**
- $h'(1) = 2$
- $h'(2) = \text{dne}$
- $h'(3) = -2$
Product Derivative Dbd121
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