1. **State the problem:**
We need to find the dimensions (radius $r$ and height $h$) of a cylindrical can that holds a volume of 1500 cm³ and minimizes the surface area (material used).
2. **Given formulas:**
- Surface area: $$A = 2\pi rh + 2\pi r^2$$
- Volume: $$V = \pi r^2 h$$
3. **Express $h$ in terms of $r$ using the volume constraint:**
$$V = \pi r^2 h = 1500 \implies h = \frac{1500}{\pi r^2}$$
4. **Substitute $h$ into the surface area formula:**
$$A = 2\pi r \left(\frac{1500}{\pi r^2}\right) + 2\pi r^2 = \frac{3000}{r} + 2\pi r^2$$
5. **Minimize $A$ by finding critical points:**
Take derivative with respect to $r$:
$$\frac{dA}{dr} = -\frac{3000}{r^2} + 4\pi r$$
6. **Set derivative to zero to find minimum:**
$$-\frac{3000}{r^2} + 4\pi r = 0$$
7. **Solve for $r$:**
$$4\pi r = \frac{3000}{r^2}$$
$$4\pi r^3 = 3000$$
$$r^3 = \frac{3000}{4\pi} = \frac{750}{\pi}$$
$$r = \sqrt[3]{\frac{750}{\pi}}$$
8. **Calculate $r$ numerically:**
$$r \approx \sqrt[3]{238.732} \approx 6.2 \text{ cm}$$
9. **Find $h$ using $r$:**
$$h = \frac{1500}{\pi (6.2)^2} \approx \frac{1500}{\pi \times 38.44} \approx \frac{1500}{120.78} \approx 12.42 \text{ cm}$$
10. **Conclusion:**
The can dimensions that minimize material are approximately:
- Radius $r \approx 6.2$ cm
- Height $h \approx 12.42$ cm
These dimensions minimize the surface area for the given volume.
Cylindrical Can C09Efd
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