Answer:



Step-by-step explanation:
<u>Optimizing With Derivatives
</u>
The procedure to optimize a function (find its maximum or minimum) consists in
:
- Produce a function which depends on only one variable
- Compute the first derivative and set it equal to 0
- Find the values for the variable, called critical points
- Compute the second derivative
- Evaluate the second derivative in the critical points. If it results positive, the critical point is a minimum, if it's negative, the critical point is a maximum
We know a cylinder has a volume of 4
. The volume of a cylinder is given by

Equating it to 4

Let's solve for h

A cylinder with an open-top has only one circle as the shape of the lid and has a lateral area computed as a rectangle of height h and base equal to the length of a circle. Thus, the total area of the material to make the cylinder is

Replacing the formula of h

Simplifying

We have the function of the area in terms of one variable. Now we compute the first derivative and equal it to zero

Rearranging

Solving for r

![\displaystyle r=\sqrt[3]{\frac{4}{\pi }}\approx 1.084\ feet](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Csqrt%5B3%5D%7B%5Cfrac%7B4%7D%7B%5Cpi%20%7D%7D%5Capprox%201.084%5C%20feet)
Computing h

We can see the height and the radius are of the same size. We check if the critical point is a maximum or a minimum by computing the second derivative

We can see it will be always positive regardless of the value of r (assumed positive too), so the critical point is a minimum.
The minimum area is


Answer:
r = 7 cm; l = 11cm
The circle encloses more area than the square
Step-by-step explanation:
(a) Radius of circle
The formula for the circumference of a circle is
A = 2πr
r = A/(2π)
Data:
C = 44 in
Calculation:
r = 44/(2 × 22/7)
= 44/2 × 7/22
= 2/2 × 7
= 7 in
(b) Side of square
P = 4l
l = P/4
= 44/4
= 11 in
(c) Areas
(i) Circle
A = πr²
= 22/7 × 7²
= 22/7 × 49
= 22 × 7
= 154 cm²
(ii) Square
A = l²
= 11²
= 121 cm²
The circle encloses more area than the square.
There are two ways to evaluate the square root of 864: using a calculator, and simplifying the root.
The first method is simplifying the root. While this doesn't give you an exact value, it reduces the number inside the root.
Find the prime factorization of 864:

Take any number that is repeated twice in the square root, and move it outside of the root:





The simplified form of √864 will be 12√6.
The second method is evaluating the root. Using a calculator, we can find the exact value of √864.
Plugged into a calculator and rounded to the nearest hundredths value, √864 is equal to 29.39. Because square roots can be negative or positive when evaluated, this means that √864 is equal to ±29.39.