Answer:
41.74 and 41.89
Step-by-step explanation:
Answer: 
<u>Step-by-step explanation:</u>

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


Step-by-step explanation:
Make sure to see the photo I tried to explain every part there
Answer:
(2, - 3 )
Step-by-step explanation:
Given the 2 equations
2x - 3y = 13 → (1)
x + 2y = - 4 → (2)
Rearrange (2) expressing x in terms of y by subtracting 2y from both sides
x = - 4 - 2y → (3)
Substitute x = - 4 - 2y into (1)
2(- 4 - 2y) - 3y = 13 ← distribute and simplify left side
- 8 - 4y - 3y = 13
- 8 - 7y = 13 ( add 8 to both sides )
- 7y = 21 ( divide both sides by - 7 )
y = - 3
Substitute y = - 3 into (3) for corresponding value of x
x = - 4 - 2(- 3) = - 4 + 6 = 2
Solution is (2, - 3 )