Answer:
The dimensions that minimize the cost of materials for the cylinders have radii of about 3.628 cm and heights of about 7.256 cm.
Step-by-step explanation:
A cylindrical can holds 300 cubic centimeters, and we want to find the dimensions that minimize the cost for materials: that is, the dimensions that minimize the surface area.
Recall that the volume for a cylinder is given by:
Substitute:
Solve for <em>h: </em>
Recall that the surface area of a cylinder is given by:
We want to minimize this equation. To do so, we can find its critical points, since extrema (minima and maxima) occur at critical points.
First, substitute for <em>h</em>.
Find its derivative:
Solve for its zero(s):
![\displaystyle \begin{aligned} (0) &= 4\pi r - \frac{600}{r^2} \\ \\ 4\pi r - \frac{600}{r^2} &= 0 \\ \\ 4\pi r^3 - 600 &= 0 \\ \\ \pi r^3 &= 150 \\ \\ r &= \sqrt[3]{\frac{150}{\pi}} \approx 3.628\text{ cm}\end{aligned}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cbegin%7Baligned%7D%20%280%29%20%26%3D%204%5Cpi%20r%20%20-%20%5Cfrac%7B600%7D%7Br%5E2%7D%20%5C%5C%20%5C%5C%204%5Cpi%20r%20-%20%5Cfrac%7B600%7D%7Br%5E2%7D%20%26%3D%200%20%5C%5C%20%5C%5C%204%5Cpi%20r%5E3%20-%20600%20%26%3D%200%20%5C%5C%20%5C%5C%20%5Cpi%20r%5E3%20%26%3D%20150%20%5C%5C%20%5C%5C%20r%20%26%3D%20%5Csqrt%5B3%5D%7B%5Cfrac%7B150%7D%7B%5Cpi%7D%7D%20%5Capprox%203.628%5Ctext%7B%20cm%7D%5Cend%7Baligned%7D)
Hence, the radius that minimizes the surface area will be about 3.628 centimeters.
Then the height will be:
![\displaystyle \begin{aligned} h&= \frac{300}{\pi\left( \sqrt[3]{\dfrac{150}{\pi}}\right)^2} \\ \\ &= \frac{60}{\pi \sqrt[3]{\dfrac{180}{\pi^2}}}\approx 7.25 6\text{ cm} \end{aligned}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%20%5Cbegin%7Baligned%7D%20h%26%3D%20%5Cfrac%7B300%7D%7B%5Cpi%5Cleft%28%20%5Csqrt%5B3%5D%7B%5Cdfrac%7B150%7D%7B%5Cpi%7D%7D%5Cright%29%5E2%7D%20%20%5C%5C%20%5C%5C%20%26%3D%20%5Cfrac%7B60%7D%7B%5Cpi%20%5Csqrt%5B3%5D%7B%5Cdfrac%7B180%7D%7B%5Cpi%5E2%7D%7D%7D%5Capprox%207.25%206%5Ctext%7B%20cm%7D%20%20%20%5Cend%7Baligned%7D)
In conclusion, the dimensions that minimize the cost of materials for the cylinders have radii of about 3.628 cm and heights of about 7.256 cm.
Answer:
6.25%
Step-by-step explanation:
We first begin by solving for the original price of the cell phone.
if 2400 = 125%
x = 100%
By cross multplying, we get
125x = 2400 * 100
x = 240000/125
x = 1920rs
To find the profit percentage on the new sale price, we repeat another set of equations
100% = 1920
x = 2040
1920x = 2040 * 100
x = 204000/1920
x = 106.25%
His new profit percentage is 6.25%
Answer:
3/-20
Step-by-step explanation:
I think you were asking for the slope for these, so that's what I gave you, sorry if you needed something else
Answer:
B, C, E, F
Step-by-step explanation:
The following relationships apply.
- the diagonals of a parallelogram bisect each other
- the diagonals of a rectangle are congruent
- the diagonals of a rhombus meet at right angles
- a rectangle is a parallelogram
- a parallelogram with congruent adjacent sides is a rhombus
__
CEDF has diagonals that bisect each other, and it has congruent adjacent sides. It is a parallelogram and a rhombus, but not a rectangle. (B and C are true.)
ABCD has congruent diagonals that bisect each other. It is a parallelogram and a rectangle, but not a rhombus. (There is no indication adjacent sides are congruent, or that the diagonals meet at right angles.) (E and F are true.)
The true statements are B, C, E, F.
