Answer:
136.1
Step-by-step explanation:
Given Information:
Area of rectangle = 16 square feet
Required Information:
Least amount of material = ?
Answer:
x = 4 ft and y = 4 ft
Step-by-step explanation:
We know that a rectangle has area = xy and perimeter = 2x + 2y
We want to use least amount of material to design the sandbox which means we want to minimize the perimeter which can be done by taking the derivative of perimeter and then setting it equal to 0.
So we have
xy = 16
y = 16/x
p = 2x + 2y
put the value of y into the equation of perimeter
p = 2x + 2(16/x)
p = 2x + 32/x
Take derivative with respect to x
d/dt (2x + 32/x)
2 - 32/x²
set the derivative equal to zero to minimize the perimeter
2 - 32/x² = 0
32/x² = 2
x² = 32/2
x² = 16
x =
ft
put the value of x into equation xy = 16
(4)y = 16
y = 16/4
y = 4 ft
So the dimensions are x = 4 ft and y = 4 ft in order to use least amount of material.
Verification:
xy = 16
4*4 = 16
16 = 16 (satisfied)
Answer: 50
Step-by-step explanation:
3(50)-14=136
Answer: 5
Step-by-step explanation: Let x = the number
x^10 ÷ x^7 = 125
x^3 = 125
x = 5
Answer:
40 units per sec
Step-by-step explanation:
The average rate of change in this case is the change in y over the first three seconds (which is 220 - 100, or 120) divided by the elapsed time (which is 3 seconds).
120
Thus, we have ------------ = 40 units per sec
3