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Sphinxa [80]
3 years ago
8

A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 40 cm/s. Find the rate at which th

e area within the circle is increasing after each of the following.
after 1 s = after 3 s = after 7 s =
Mathematics
1 answer:
Sonja [21]3 years ago
5 0
Given : dr/dt = 40 cm/s A = πr^2 dA/dt = 2π r dr/dt case 1: when s = 1, r = 40 dA/dt = 2π(40)(40) = 3200π cm^2/sec case 2: when s = 3, r = 3(4) = 120 cm dA/dt = 2π(120)(40) = 9600π cm^2/sec case 3: ... your turn .....
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1!<br><br><br><br><br> please help!!<br><br><br> math geniuses where r uuuu<br><br><br><br> help!
Serhud [2]

Answer:

i think option d tan theta =0

3 0
2 years ago
The last time Sophie checked, the corn stalks in her back yard were 56 inches tall. Now they are 25% taller. How tall are the st
Lelu [443]

Answer: 70 inches

Step-by-step explanation: 25 percent of 56 is 14. 14 + 56 = 70.

6 0
2 years ago
Read 2 more answers
The radius of a sphere is 12 units. Find the volume of the sphere. Write your answer in terms of pi.
stiv31 [10]

Answer:

V = 2304π units³

Step-by-step explanation:

The volume (V) of a sphere is calculated as

V = \frac{4}{3}πr³ ( where r is the radius ) , then

V = \frac{4}{3}π × 12³

   = \frac{4}{3} π × 1728

   = 4π × 576

   = 2304π units³

5 0
2 years ago
The manager wants to advertise that anybody who isn't served within a certain number of minutes gets a free hamburger. But she d
aksik [14]

Answer:

The number of minutes advertisement should use is found.

x ≅ 12 mins

Step-by-step explanation:

(MISSING PART OF THE QUESTION: AVERAGE WAITING TIME = 2.5 MINUTES)

<h3 /><h3>Step 1</h3>

For such problems, we can use probability density function, in which probability is found out by taking integral of a function across an interval.

Probability Density Function is given by:

f(t)=\left \{ {{0 ,\-t

Consider the second function:

f(t)=\frac{e^{-t/\mu}}{\mu}\\

Where Average waiting time = μ = 2.5

The function f(t) becomes

f(t)=0.4e^{-0.4t}

<h3>Step 2</h3>

The manager wants to give free hamburgers to only 1% of her costumers, which means that probability of a costumer getting a free hamburger is 0.01

The probability that a costumer has to wait for more than x minutes is:

\int\limits^\infty_x {f(t)} \, dt= \int\limits^\infty_x {}0.4e^{-0.4t}dt

which is equal to 0.01

<h3>Step 3</h3>

Solve the equation for x

\int\limits^{\infty}_x {0.4e^{-0.4t}} \, dt =0.01\\\\\frac{0.4e^{-0.4t}}{-0.4}=0.01\\\\-e^{-0.4t} |^\infty_x =0.01\\\\e^{-0.4x}=0.01

Take natural log on both sides

ln (e^{-0.4x})=ln(0.01)\\-0.4x=ln(0.01)\\-0.4x=-4.61\\x= 11.53

<h3>Results</h3>

The costumer has to wait x = 11.53 mins ≅ 12 mins to get a free hamburger

3 0
2 years ago
Write an algebraic expression for the phrase the sum of g and 3
Paraphin [41]
The sum of g and 3. 

The sum of two values is added together. 

g+3

You would add g to 3 since it is their sum the statement is asking for.

I hope this helps!
~kaikers
3 0
3 years ago
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