The rate a which the surface area, S, decreases is

The surface area is
S = 4πr²
where r = the radius at time t.
Therefore

When r = 3 cm, obtain
![\frac{dr}{dt}]_{r=3} = - \frac{1}{3} \, cm/s](https://tex.z-dn.net/?f=%20%5Cfrac%7Bdr%7D%7Bdt%7D%5D_%7Br%3D3%7D%20%3D%20-%20%5Cfrac%7B1%7D%7B3%7D%20%5C%2C%20cm%2Fs%20%20)
Answer: -1/3 cm/s (or -0.333 cm/s)
It’s b becuse if u multiple it’s is b
Answer:
.
Step-by-step explanation:
Graph :
Choose any two points. (0 , 2) and (-1 , -2)
Rate of change = Change in y ÷ Change in x

Table:
Rate of change = ![\frac{-2-[-6]}{2-0}](https://tex.z-dn.net/?f=%5Cfrac%7B-2-%5B-6%5D%7D%7B2-0%7D)

Answer:
18.66 ft/s
Step-by-step explanation:
The distance between you and the elevator is given by:

The rate of change for the distance between you and the elevator is given by:



Applying the chain rule:

Therefore, at x=300 and y = 500, dy/dt is:

The elevator is descending at 18.66 ft/s.
Answer:
Area of trapeze= (B+b):2×h
Therefore : (7+10):2×4=34
Good luck!