Answer:
Side of 22 and height of 11
Step-by-step explanation:
Let s be the side of the square base and h be the height of the tank. Since the tank volume is restricted to 5324 ft cubed we have the following equation:


As the thickness is already defined, we can minimize the weight by minimizing the surface area of the tank
Base area with open top 
Side area 4sh
Total surface area 
We can substitute 


To find the minimum of this function, we can take the first derivative, and set it to 0



![s = \sqrt[3]{10648} = 22](https://tex.z-dn.net/?f=s%20%3D%20%5Csqrt%5B3%5D%7B10648%7D%20%3D%2022)

Answer:
The shortest distance is 2.2 miles
Step-by-step explanation:
we know that
The shortest distance you must travel to reach the river is the perpendicular distance to the river
step 1
Find the slope of the line perpendicular to the river
we have

The slope of the river is m=3
Remember that if two lines are perpendicular, then their slopes are opposite reciprocal (the product of their slopes is -1)
therefore
The slope of the line perpendicular to the river is

step 2
Find the equation of the line into point slope form

we have


substitute

step 3
Find the intersection point of the river and the line perpendicular to the river
we have
------> equation A
-----> equation B
Solve the system by graphing
The intersection point is (-0.1,1,7)
see the attached figure
step 3
Find the distance between the points (2,1) and (-0,1,1.7)
the formula to calculate the distance between two points is equal to
substitute
A = {1, 2, 5, 6, 8}
{1} U {2, 5, 6, 8}
{2} U {1, 5, 6, 8}
{5} U {1, 2, 6, 8}
{6} U {1, 2, 5, 8}
{8} U {1, 2, 5, 6}
{1, 2} U {5, 6, 8}
{1, 5} U {2, 6, 8}
{1, 6} U {2, 5, 8}
{1, 8} U {2, 5, 6}
{1, 2, 5} U {6, 8}
{1, 2, 6} U {5, 8}
{1, 2, 8} U {5, 6}
{1, 5, 6} U {2, 8}
{1, 5, 8} U {2, 6}
{1, 6, 8} U {2, 5}
The answer is 15 distinct pairs of disjoint non-empty subsets.