1. The problem asks whether the Extreme Value Theorem (EVT) guarantees an absolute maximum and minimum for each function on the closed interval $[0,6]$.
2. The EVT states: If a function is continuous on a closed interval $[a,b]$, then it must have both an absolute maximum and an absolute minimum on that interval.
3. For each function, we check continuity on $[0,6]$:
a. $f(x) = 8x^5 - 7x^2 + 3x - 4$ is a polynomial, which is continuous everywhere, so it is continuous on $[0,6]$.
b. $g(x) = \frac{2x + 1}{x - 5}$ has a denominator zero at $x=5$, which lies in $[0,6]$, so $g$ is not continuous on $[0,6]$.
c. $h(x) = \begin{cases} 2x + 2, & 0 \leq x < 3 \\ x^2, & 3 < x \leq 6 \end{cases}$ is piecewise defined with a jump at $x=3$ (since $\lim_{x \to 3^-} h(x) = 2(3)+2=8$ and $\lim_{x \to 3^+} h(x) = 3^2=9$), so $h$ is not continuous on $[0,6]$.
4. Conclusion:
a. $f$ satisfies EVT conditions, so it has absolute max and min on $[0,6]$.
b. $g$ is not continuous on $[0,6]$, so EVT does not guarantee absolute extrema.
c. $h$ is not continuous on $[0,6]$, so EVT does not guarantee absolute extrema.
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5. Next problem: Find critical points of $f(x) = x^3 + 10x^2 + 12x - 4$.
6. Critical points occur where $f'(x) = 0$ or $f'(x)$ is undefined.
7. Compute derivative:
$$f'(x) = 3x^2 + 20x + 12$$
8. Set derivative equal to zero:
$$3x^2 + 20x + 12 = 0$$
9. Divide entire equation by 3:
$$\cancel{3}x^2 + \cancel{20}x + \cancel{12} = 0 \Rightarrow x^2 + \frac{20}{3}x + 4 = 0$$
10. Use quadratic formula $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$ with $a=1$, $b=\frac{20}{3}$, $c=4$:
$$x = \frac{-\frac{20}{3} \pm \sqrt{\left(\frac{20}{3}\right)^2 - 4 \cdot 1 \cdot 4}}{2}$$
11. Calculate discriminant:
$$\left(\frac{20}{3}\right)^2 - 16 = \frac{400}{9} - 16 = \frac{400}{9} - \frac{144}{9} = \frac{256}{9}$$
12. Square root of discriminant:
$$\sqrt{\frac{256}{9}} = \frac{16}{3}$$
13. Substitute back:
$$x = \frac{-\frac{20}{3} \pm \frac{16}{3}}{2} = \frac{\frac{-20 \pm 16}{3}}{2} = \frac{-20 \pm 16}{6}$$
14. Calculate both solutions:
$$x_1 = \frac{-20 + 16}{6} = \frac{-4}{6} = -\frac{2}{3}$$
$$x_2 = \frac{-20 - 16}{6} = \frac{-36}{6} = -6$$
15. Therefore, the critical points are at $x = -\frac{2}{3}$ and $x = -6$.
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Final answers:
- EVT guarantees absolute extrema only for $f(x)$ in part 1.
- Critical points of $f(x) = x^3 + 10x^2 + 12x - 4$ are $x = -\frac{2}{3}$ and $x = -6$.
Extreme Value Critical Points 4Ae73D
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