1. **State the problem:** Find the equation of the normal line to the function $f(x) = x^3 - 3x + 1$ at its local maximum point.
2. **Find the local maximum point:**
- First, find the derivative $f'(x)$ to locate critical points.
$$f'(x) = 3x^2 - 3$$
- Set $f'(x) = 0$ to find critical points:
$$3x^2 - 3 = 0$$
$$3(x^2 - 1) = 0$$
$$\cancel{3}(x^2 - 1) = 0$$
$$x^2 - 1 = 0$$
$$x^2 = 1$$
$$x = \pm 1$$
3. **Determine which critical point is a local maximum:**
- Find the second derivative:
$$f''(x) = 6x$$
- Evaluate $f''(x)$ at $x = -1$:
$$f''(-1) = 6(-1) = -6 < 0$$
- Since $f''(-1) < 0$, $x = -1$ is a local maximum.
4. **Find the coordinates of the local maximum point:**
$$f(-1) = (-1)^3 - 3(-1) + 1 = -1 + 3 + 1 = 3$$
So the local maximum point is $(-1, 3)$.
5. **Find the slope of the tangent line at $x = -1$:**
$$f'(-1) = 3(-1)^2 - 3 = 3(1) - 3 = 0$$
6. **Find the slope of the normal line:**
- The normal line is perpendicular to the tangent line, so its slope is the negative reciprocal of the tangent slope.
- Since the tangent slope is $0$, the normal slope is undefined, meaning the normal line is vertical.
7. **Write the equation of the normal line:**
- A vertical line through $x = -1$ is:
$$x = -1$$
**Final answer:** The equation of the normal line at the local maximum point is $x = -1$.
Normal Line 0741Fe
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