1. **State the problem:**
We are given a function $f$ defined on intervals $[0,8]$ and $[2,8]$ with properties that satisfy Rolle's Theorem and the Mean Value Theorem (MVT). We need to estimate values of $c$ where the derivative $f'(c)$ meets certain conditions and interpret the theorems' conclusions.
2. **Rolle's Theorem (part a):**
Rolle's Theorem states that if a function $f$ is continuous on $[a,b]$, differentiable on $(a,b)$, and $f(a) = f(b)$, then there exists at least one $c$ in $(a,b)$ such that
$$f'(c) = 0.$$
3. **Apply Rolle's Theorem:**
Given $f(0) = f(8) = 0$ and $f$ is continuous and differentiable on $[0,8]$, there must be some $c$ in $(0,8)$ with $f'(c) = 0$. The graph shows a vertex at approximately $x=4$, where the tangent is horizontal, so
$$c = 4.$$
4. **Interpretation of Rolle's Theorem (part b):**
The conclusion means there is a point $c$ where the tangent line is horizontal (slope zero). So the correct interpretation is:
"There is a value of $c$ in $(0,8)$ such that the tangent line to $f$ at $x=c$ is horizontal."
5. **Mean Value Theorem (part c):**
MVT states that if $f$ is continuous on $[a,b]$ and differentiable on $(a,b)$, then there exists $c$ in $(a,b)$ such that
$$f'(c) = \frac{f(b) - f(a)}{b - a}.$$
6. **Apply MVT:**
On $[2,8]$, $f$ is continuous and differentiable. The average rate of change is
$$\frac{f(8) - f(2)}{8 - 2}.$$
From the graph, the slope of the secant line between $(2,f(2))$ and $(8,f(8))$ is positive and the tangent line with this slope occurs near $c=5$ (not $11$ as stated). Since $11$ is outside $(2,8)$, the correct estimate should be near $c=5$.
7. **Interpretation of MVT (part d):**
The conclusion means there is a $c$ where the tangent line is parallel to the secant line through $(2,f(2))$ and $(8,f(8))$. The best interpretation is:
"There is a value of $c$ in $(2,8)$ such that the tangent line to $f$ at $x=c$ is parallel to the secant line passing through $(2,f(2))$ and $(8,f(8))$."
**Final answers:**
- (a) $c = 4$
- (b) Tangent line at $c$ is horizontal
- (c) $c \approx 5$ (corrected estimate)
- (d) Tangent line at $c$ is parallel to secant line
Rolle Mean Value 7Fa8D8
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