Answer:
The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Step-by-step explanation:
The area of a sphere is given by the following formula:
![A = 4\pi r^{2}](https://tex.z-dn.net/?f=A%20%3D%204%5Cpi%20r%5E%7B2%7D)
In which A is the area, measured in cm², and r is the radius, measured in cm.
Assume that the radius r of a sphere is expanding at a rate of 40 cm/min.
This means that ![\frac{dr}{dt} = 40](https://tex.z-dn.net/?f=%5Cfrac%7Bdr%7D%7Bdt%7D%20%3D%2040)
Determine the rate of change in surface area when r = 20 cm.
This is
when
. So
![A = 4\pi r^{2}](https://tex.z-dn.net/?f=A%20%3D%204%5Cpi%20r%5E%7B2%7D)
Applying implicit differentiation.
We have two variables, A and r, so:
![\frac{dA}{dt} = 8r\pi \frac{dr}{dt}](https://tex.z-dn.net/?f=%5Cfrac%7BdA%7D%7Bdt%7D%20%3D%208r%5Cpi%20%5Cfrac%7Bdr%7D%7Bdt%7D)
![\frac{dA}{dt} = 8*20\pi*40](https://tex.z-dn.net/?f=%5Cfrac%7BdA%7D%7Bdt%7D%20%3D%208%2A20%5Cpi%2A40)
![\frac{dA}{dt} = 20106.19](https://tex.z-dn.net/?f=%5Cfrac%7BdA%7D%7Bdt%7D%20%3D%2020106.19)
The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Answer:
-22
Step-by-step explanation:
The function y=400-22x is a linear equation in the form y=mx + b. Although they put "mx" after "b" so the equation doesn't start with a negative.
"m" is rate of change, or the slope if graphed.
The negative means "y" decreases as "x" increases. On a graph, it decreases left to right.
Answer:
-9 < x
Step-by-step explanation:
-3x - 7 < 20
+ 7 + 7
___________
-3x < 27
___ ___
-3 -3
x > -9 [Whenever you <em>divide</em><em> </em>or <em>multiply</em><em> </em>by a negative, reverse the inequality symbol.]
The above answer is written in reverse, which is the exact same result.
I am joyous to assist you anytime.
Answer:
y=x2
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Answer:
In descending order, 1, 4, 3