1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kobusy [5.1K]
3 years ago
5

When you cough,the radius of your trachea (windpipe) decreases,affecting the speed S of the air in the trachea. If r0 is the nor

mal radius of the trachea, the relationship between the speed S of the air and the radius r of the trachea during a cough is given by a function of the form
S(r) = (r0 - r) ar^2

where a is positive constant. Find the radius r for which the speed of the air is greatest.
Mathematics
2 answers:
elixir [45]3 years ago
6 0

Answer: 2r(0)/3.

Step-by-step explanation:

So, we are given one Important data or o or parameter in the question above and that is the function of the form which is given below(that is);

S(r) = (r0 - r) ar^2 -----------------------------(1).

We will now have to differentiate S(r) with respect to r, so, check below for the differentiation:

dS/dr = 2ar (r0 - r ) + ar^2 (-1 ) ---------;(2).

dS/dr = 2ar(r0) - 2ar^2 - ar^2.

dS/dr = - 3ar^2 + 2ar(r0) ------------------(3).

Note that dS/dr = 0.

Hence, - 3ar^2 + 2ar(r0) = 0.

Making ra the subject of the formula we have;

ra[ - 3r + 2r(0) ] = 0. -------------------------(4).

Hence, r = 0 and r = 2r(0) / 3.

If we take the second derivative of S(r) too, we will have;

d^2S/dr = -6ar + 2ar(0). -------------------(5).

+ 2ar(0) > 0 for r = 0; and r = 2r(0)/3 which is the greatest.

solniwko [45]3 years ago
6 0

Answer:

r =\frac{2r_{0}}{3}

Step-by-step explanation:

We need to take the derivative of S(r) and equal to zero to maximize the function. In this conditions we will find the radius r for which the speed of the air is greatest.

Let's take the derivative:

\frac{dS}{dr}=a(2r(r_{0}-r)+r^{2}(-1))

\frac{dS}{dr}=a(2r*r_{0}-2r^{2}-r^{2})

\frac{dS}{dr}=a(2r*r_{0}-3r^{2})

\frac{dS}{dr}=ar(2r_{0}-3r)

Let's equal it to zero, to maximize S.

0=ar(2r_{0}-3r)

We will have two solutions:

r = 0

r =\frac{2r_{0}}{3}

Therefore the value of r for which the speed of the air is greatest is r =\frac{2r_{0}}{3}.

I hope it helps you!

You might be interested in
Is the figure on the right congruent to the sample figure? EXPLAIN.
disa [49]
Yes, because they are equal and have the same measurement same size and same shape.
4 0
3 years ago
Read 2 more answers
Need help ASAP no rocky
Mademuasel [1]

Answer:

x = 12

Step-by-step explanation:

The sum of a heptagon interior angles is 900 degrees, so:

10x + 5 + 12x - 9 + 9x + 14 + 133 + 10x + 9 + 10x + 136 = 900

rearrange to make it easier to subtract/add, u don't have to do this it's optional

10x + 12x + 9x + 10x + 10x + 5 - 9 + 9 + 14 + 133 + 136 = 900

add liket terms

22x + 29x + 19 + 269 = 900

51x + 288 = 900

subtract 288 from both sides

51x = 612

divide by 51

x = 12

7 0
2 years ago
A home is purchased for $60,000 in 2001 and sold for $225,000 in 2021. Plot this on a graph. Then draw 2 lines, 1 mapping a line
astraxan [27]

Answer:

a. 3.6

b Linear

c. 2.13333

Plot a graph going up vertically by amounts 30,000  would be = 1

60,.000 would be = 2, 90,000 would be = 3 etc.

225,000 would show between 7 and 8. where marks of 15/30 = 1/2 would be counted back from 240,000 to 225,000 and between 210,000 to 240,000

After mapping the x rate must be 1 for both linear and for exponential.

The average rate of change is found when 60k = 2  and 225k = 7.5 is increasing and years shown 2001 to 2021 are shown on x axis.

=  20 years

Therefore linear shows 2 when x = 1 then shows 7.5 when x = 20

20/7.5 = 2.6

Therefore, this relationship is linear because each yyy-value is 7.5/20 more than the value before it. The x value goes up by 1 each value of 0.37 for y

When the value is exponential the y value should go up by 1 and as it is 30,000 each 1 value and x =1 goes up 2 2/3 = 2.6667 for every 30.000k to every x value.

A. 2 -2 2/3  = 2.31555.. average rate of change.for exponential  and between 3.5 and 3.7 = 3.6 average rate of change for linear.

B linear

C 2008 = 8 YEARS 8/20 X 2 = 0.8

0.8 X 2  2/3= 2.13333333 is the app value of the linear model 2008.

6 0
3 years ago
Can anyone help with this please, I am so stuck!
Finger [1]

Answer:

(x + 1)^2 + (y - 4)^2 = 8

Step-by-step explanation:

Midpoint of the diameter is the centre

So....Centre coordinates are ((-3+1)÷2 ; (2+6)÷2) = (-1;4)

Calculate the radius of the circle....

Radius = square root of [(-1+3)^2 + (4-2)^2]

;Radius = square root of 8

Then substitute the x-coordinate of the centre into the first slot....then the y-coordinate into the second slot and the radius(squared) into last slot of the equation......;

(x + 1)^2 + (y - 4)^2 = 8

4 0
3 years ago
Sara takes 1/6 of an hour to vacuum his moms car it takes 4 times that long to wash the car then it takes you to wax the car twi
Nataly [62]
<h2>Answer:</h2><h2>2 hours & 10 minutes </h2><h2>Step-by-step explanation:</h2><h2>1/6 of an hour is 10 minutes. She vacuumed for 10 minutes. It took 4 times as long to wash the car so 10 * 4 = 40. She washed the car for 40 minutes. It took her twice as long to wax the car as it did for her to wash it so 40 * 2 = 80. She waxed the car for 80 minutes. 10 + 40 + 80 = 130 minutes or 2 hours and 10 minutes. </h2>
3 0
3 years ago
Other questions:
  • In 2 weeks Simone gets 46 emails. at the same rate, how many weeks will it take for her to get 115 emails
    12·1 answer
  • Kenya jumped 7 and 1 sixth feet. Janet jumped 6 and 1 third feet. How much farther did Kenya jump?
    15·1 answer
  • Find the measure of angle 2.<br><br> 60°<br> 90°<br> 120°<br> 30°
    7·2 answers
  • Hey I need helping with solving thank you
    6·1 answer
  • According to a recent survey, 73% of all customers will return to the same grocery store. Suppose 14 customers are selected at r
    7·1 answer
  • Write a statement that indicates that the triangles in each pair are congruent.
    7·1 answer
  • 5x²-4(x²+1)<br>how to factorise this?​
    12·1 answer
  • Hi do you guys know what 42.7 x 10^3 is? i js want to comfirm my answer. please answer quickly if you know.
    10·1 answer
  • Find the sum of 2/3 and it’s additive inverse
    8·1 answer
  • What is -5/12 x 8/13 in its simplest form
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!