Critical Points Cc0B4C
1. **Problem Statement:**
Find the critical numbers, intervals of increase/decrease, and relative extrema values for the function $$f(x) = x^3 - 3x^2 + 1$$ on the interval $$[-3,3]$$.
2. **Step 1: Find the critical numbers**
Critical numbers occur where the derivative $$f'(x)$$ is zero or undefined.
Calculate the derivative:
$$f'(x) = 3x^2 - 6x$$
Set the derivative equal to zero:
$$3x^2 - 6x = 0$$
Factor out $$3x$$:
$$3x(x - 2) = 0$$
So, $$x = 0$$ or $$x = 2$$ are critical numbers.
3. **Step 2: Determine intervals of increase and decrease**
Test values in intervals determined by critical numbers: $$(-3,0)$$, $$(0,2)$$, and $$(2,3)$$.
- For $$x < 0$$, pick $$x = -1$$:
$$f'(-1) = 3(-1)^2 - 6(-1) = 3 + 6 = 9 > 0$$, so $$f$$ is increasing on $$(-3,0)$$.
- For $$0 < x < 2$$, pick $$x = 1$$:
$$f'(1) = 3(1)^2 - 6(1) = 3 - 6 = -3 < 0$$, so $$f$$ is decreasing on $$(0,2)$$.
- For $$x > 2$$, pick $$x = 3$$:
$$f'(3) = 3(3)^2 - 6(3) = 27 - 18 = 9 > 0$$, so $$f$$ is increasing on $$(2,3)$$.
4. **Step 3: Find the values of $$f(x)$$ at the relative extrema**
Evaluate $$f(x)$$ at critical points:
- At $$x=0$$:
$$f(0) = 0^3 - 3(0)^2 + 1 = 1$$
- At $$x=2$$:
$$f(2) = 2^3 - 3(2)^2 + 1 = 8 - 12 + 1 = -3$$
5. **Summary:**
- Critical numbers: $$x=0$$ and $$x=2$$.
- Increasing on $$(-3,0)$$ and $$(2,3)$$.
- Decreasing on $$(0,2)$$.
- Relative maximum at $$x=0$$ with $$f(0)=1$$.
- Relative minimum at $$x=2$$ with $$f(2)=-3$$.