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cluponka [151]
3 years ago
15

Coughing forces the trachea (windpipe) to contract, which in turn affects the velocity of the air through the trachea. The veloc

ity of the air during coughing can be modeled by v = k(R – r)r2, 0 ≤ r < R, where k is a constant, R is the normal radius of the trachea, and r is the radius during coughing. What radius r will produce the maximum air velocity?
Mathematics
1 answer:
Rzqust [24]3 years ago
8 0
To find the maximum velocity you have to differentiate the function respect to r.

v = k(R - r)r^2 = kRr^2 - krr^2 = kRr^2 - kr^3

k and R are constants.

=> v' = 2kRr - 3kr^2 = kr(2R - 3r)

maximum velocity => v' = 0 => kr(2R - 3r) = 0

r = 0 or 2R - 3r = 0 => r = 2R / 3

Answer: r = 2R / 3




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URGENT PLEASE HELP ME, ITS DUE IN A HOUR ​
Olegator [25]

Answer:

Area of gray region = 8x^2+8x-7

Step-by-step explanation:

The area covered by the furniture can be subtracted from the total area of the room to calculate the area of the gray region.

<em>Total</em> area of the room: 13x^2+7x-2

Area taken up by furniture: 5x^2-x+5

Area of gray region = total area of the room - area taken up by furniture

Area of gray region = 13x^2+7x-2-(5x^2-x+5)

Remember to distribute the negative sign:

Area of gray region = 13x^2+7x-2-5x^2+x-5

Combine like terms:

Area of gray region = 8x^2+8x-7

7 0
3 years ago
Read 2 more answers
60 students want lemonade and 16 students want iced tea. What is the ratio of the number of students who want iced tea to the nu
Burka [1]

Answer:

16:60 = 4/15

Step-by-step explanation:

3 0
3 years ago
Find the radius of convergence, then determine the interval of convergence
galben [10]

The radius of convergence R is 1 and the interval of convergence is (-3, -1) for the given power series. This can be obtained by using ratio test.  

<h3>Find the radius of convergence R and the interval of convergence:</h3>

Ratio test is the test that is used to find the convergence of the given power series.  

First aₙ is noted and then aₙ₊₁ is noted.

For  ∑ aₙ,  aₙ and aₙ₊₁ is noted.

\lim_{n \to \infty} |\frac{a_{n+1}}{a_{n} }| = β

  • If β < 1, then the series converges
  • If β > 1, then the series diverges
  • If β = 1, then the series inconclusive

Here a_{k} = \frac{(x+2)^{k}}{\sqrt{k} }  and  a_{k+1} = \frac{(x+2)^{k+1}}{\sqrt{k+1} }

   

Now limit is taken,

\lim_{n \to \infty} |\frac{a_{n+1}}{a_{n} }| = \lim_{n \to \infty} |\frac{(x+2)^{k+1} }{\sqrt{k+1} }/\frac{(x+2)^{k} }{\sqrt{k} }|

= \lim_{n \to \infty} |\frac{(x+2)^{k+1} }{\sqrt{k+1} }\frac{\sqrt{k} }{(x+2)^{k}}|

= \lim_{n \to \infty} |{(x+2) } }{\sqrt{\frac{k}{k+1} } }}|

= |{x+2 }|\lim_{n \to \infty}}{\sqrt{\frac{k}{k+1} } }}

= |{x+2 }| < 1

- 1 < {x+2 } < 1

- 1 - 2 < x < 1 - 2

- 3 < x < - 1

 

We get that,

interval of convergence = (-3, -1)

radius of convergence R = 1

Hence the radius of convergence R is 1 and the interval of convergence is (-3, -1) for the given power series.

Learn more about radius of convergence here:

brainly.com/question/14394994

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5 0
1 year ago
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A large party balloon is being filled with helium at a constant rate. After 8 seconds, there is 2.5L of helium in the balloon.
raketka [301]

Answer:

32 seconds

Step-by-step explanation:

first 8 secknds gives us the value of set 2.5l

2.5L to make 10 =

10÷2.5=4

That said 2.5L fills 1pL by 4 giving us;

4×2.5= 10L

7 0
1 year ago
Please help!!!! I don’t get this
Stella [2.4K]
The trig function sine, often abbreviated as "sin" (pronounced the same way as "sine"), is essentially the ratio or fraction of the opposite side and the hypotenuse. See the attached image for a reference.

The leg opposite angle B is side AC. Note how B is not present in the sequence "AC". Visually, we are as far away as possible from point B. This side is 16 units long. So AC = 16

The hypotenuse is the longest side of the right triangle. Always always always. This longest side is opposite the largest angle (90 degrees). Therefore the hypotenuse is BC = 17.46

In summary so far, we have,
opposite side = AC = 16
hypotenuse BC = 17.46

Let's use those values to compute sin(B)

sin(Angle) = opposite/hypotenuse
sin(B) = AC/BC
sin(B) = 16/17.46
sin(B) = 0.916 (this is approximate)
sin(B) = 0.92 (rounding to nearest hundredth)

This points to the final answer of choice A) 0.92

--------------------------------

Edit: Sorry nearly forgot about the reference image. I attached it just now.

4 0
3 years ago
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