Consider again the system dx/dt = x(1 − x − y), (i) dy/dt = y(0.75 − y − 0.5x), which appeared in Example 1 of Section 7.3. A constant-effort model, applied to the species x alone, assumes that the rate of growth of x is altered by including the term −Ex, where E is a positive constant measuring the effort invested in harvesting members of species x. This assumption means that, for a given effort E, the rate of catch is proportional to the population x, and that for a given population x the rate of catch is proportional to the effort E. Based on this assumption, Eqs. (i) are replaced by dx/dt = x(1 − x − y) − Ex = x(1 − E − x − y), dy/dt = y(0.75 − y − 0.5x). (ii) (c) Draw a direction field and/or a phase portrait for E = E0 and for values of E slightly less than and slightly greater than E0.

Answers

Answer 1

Using mathematical software such as MATLAB, Python with matplotlib, or other graphing tools to plot the direction field and phase portrait based on the given equations and parameters.

To draw a direction field and/or a phase portrait for the given system of equations, we need to plot representative vectors in the x-y plane based on the given differential equations. The vectors will indicate the direction of the solutions at different points.

Let's first draw the direction field for E = E0, where E0 is a constant effort.

Direction Field:

To plot the direction field, we choose a grid of points in the x-y plane and calculate the corresponding vectors based on the given differential equations.

Choose a suitable range for x and y, and divide the range into small intervals or grid points. For example, let's choose the range -1 ≤ x ≤ 2 and -1 ≤ y ≤ 2, and divide the range into intervals of 0.2.

For each grid point (x, y), calculate the values of dx/dt and dy/dt using the given equations dx/dt = x(1 − E − x − y) and dy/dt = y(0.75 − y − 0.5x). These values will give us the components of the vectors at each point.

Plot arrows or line segments at each grid point with lengths proportional to the magnitude of the vectors and directions indicating the direction of the vectors.

Repeat this process for multiple grid points to cover the entire range and obtain a representative direction field.

Phase Portrait:

To draw the phase portrait, we need to plot the trajectories or solutions of the differential equations in the x-y plane.

Choose a set of initial conditions (x0, y0) and solve the differential equations numerically or graphically to obtain the trajectories or solution curves. Use different initial conditions to explore different behaviors of the system.

Plot the obtained trajectories or solution curves on the x-y plane.

Repeat this process for different sets of initial conditions to get an overall view of the phase portrait.

Note that for values of E slightly less than and slightly greater than E0, you can repeat the above steps with the corresponding values of E to observe any changes in the direction field or phase portrait.Unfortunately, I am unable to generate visual plots directly in this text-based format. I suggest using mathematical software such as MATLAB, Python with matplotlib, or other graphing tools to plot the direction field and phase portrait based on the given equations and parameters.

To know more about MATLAB.

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Related Questions

Please help me! 20 points!
Enter your answer and show all the steps that you use to solve this problem in the space provided.

simplify
(in attachment)

Answers

Answer:

12 1/4 or (Decimal: 12.25)

Step-by-step explanation:

(3 1/2) (3 1/2)

= 7/2 (3 1/2)

= 7/2 (7/2)

= 49/4

= 12 1/4

   I hope I helped you!!

Step-by-step explanation:

When we multiplying, we find the sum of the exponents so

[tex]3 {}^{ \frac{1}{2} } \times 3 {}^{ \frac{1}{2} } \\ {3}^{ \frac{1}{2} + \frac{1}{2} } \\ = {3}^{ \frac{2}{2} } \\ = 3[/tex]

Each pair of polygons is similar. Find each missing side measure. two polygons 12 on top 5 on bottom second polygon 48 on top x on bottom

Answers

Answer:

[tex]x = 20[/tex]

Step-by-step explanation:

Given

First Polygon:

[tex]Top = 12[/tex]

[tex]Bottom =5[/tex]

Second Polygon

[tex]Top = 48[/tex]

[tex]Bottom =x[/tex]

Required

Find x

Since both polygons are similar, then:

[tex]Ratio = Top:Bottom[/tex]

For the first:

[tex]Ratio = 12:5[/tex]

For the second

[tex]Ratio = 48:x[/tex]

Equate both ratios

[tex]12:5 = 48:x[/tex]

Express as fraction

[tex]\frac{12}{5} = \frac{48}{x}[/tex]

Cross Multiply

[tex]12 * x = 48 * 5[/tex]

Solve for x

[tex]x = \frac{48 * 5}{12}[/tex]

[tex]x = \frac{240}{12}[/tex]

[tex]x = 20[/tex]

Help me please I am a idiot who doesn’t get math

Answers

To calculate the cuboid's volume, use height×width×length which is 11×11×16

For the cylinder's volume, use πr²h. in this case, it is 3.14×4²×9

Add up the two answers you get and that's the solution

PLEASE HELPP!!!!

ive been stuck on this for 3 days i feel clueless

Answers

Answer:

C.

Step-by-step explanation:

I think im right!

Hopefully it helps!

Answer:

the answer is letter C I'm sure

A cell phone costs $750 and loses 28% of its value each year. Write an exponential decay function to represent this situation.

1. f(x)= 750 • 0.72^x
2. f(x)= 0.72 • 750^x
3. f(x)= 750 • 0.28^x
4. f(x)= 0.28 • 750^x

Answers

Answer:

1. [tex]f(x) = 750\cdot 0.72^{x}[/tex]

Step-by-step explanation:

The cell phone experiments an exponential depreciation, which is defined by the following formula:

[tex]f(x) = C_{o}\cdot (1-r)^{x}[/tex], for [tex]0<r< 1[/tex]. (1)

Where:

[tex]C_{o}[/tex] - Initial cost, measured in monetary units.

[tex]r[/tex] - Depreciation rate, no unit.

[tex]x[/tex] - Time, measured in years.

[tex]f(x)[/tex] - Current value of the cell phone, measured in monetary units.

If we know that [tex]C_{o} = \$\,750[/tex] and [tex]r = 0.28[/tex], then the exponential decay function that represents the situation is:

[tex]f(x) = 750\cdot 0.72^{x}[/tex]

Which means that correct answer is 1.

Select the three inequalities that have n = 3 in the solution set
A. n + 5 < 9
B. 13 n < 1
C. 3n + 1 >7
D. 3n > 9.5
E. n-2<5

Answers

Answer:

Its just E

I'm sorry if I'm wrong

Answer: A, C, E

Solve for all the inequalitites.

n + 5 < 9

n < 9 - 5

n < 4

∴ n = 3 is a part of the solution set.

13n < 1

n < 1/13

∴ This definitely doesn't include n = 3.

3n + 1 > 7

3n > 6

n > 2

∴ n = 3 is part of the solution because n is larger than 2.

3n > 9.5

n > 9.5 ÷ 3

n > 3.16666666

∴ n = 3 is not part of the solution set.

n - 2 < 5

n < 5 + 2

n < 7

∴ n = 3 is a part of the solution set.

Complete the sentence.

Answers

Answer:

50 more

Step-by-step explanation:

Answer:

50 more than............

What is the value of x

Answers

Answer:

x=12the opposite side of parallelogram are equal

Answer:

8

Step-by-step explanation:

Since, intercepts made by parallel lines on transversals are in proportion.

Therefore,

[tex] \frac{x}{24} = \frac{12}{36} \\ \\ \frac{x}{24} = \frac{1}{3} \\ \\ x = \frac{24}{3} \\ \\ x = 8[/tex]

what is 3/7 as decimal

Answers

Answer:

0.428571429

Step-by-step explanation:

hi help again lol :)​

Answers

Answer:

Please mark brainleiest

Step-by-step explanation:

Answer is B

Step-by-step explanation:

B if you divided all the y values by x you will get 0.9

Which shows the numbers ordered from least to greatest? 9.129, 9.37, 9.3, 9.219

Answers

Least to greatest: 9.129,9.219,9.3,9.37

Hope this helps.

Answer:

9.129 then , 9.219 then , 9.3 then , 9.37

Step-by-step explanation:

The Milgram Family drove 440 miles on 20 gallons of gas. At this rate, how many miles can they drive on 25 gallons of gas? *

Answers

Answer:550

Step-by-step explanation: first you need to find the unit rate ( or how many miles per gallon) by dividing 440 by 20 which would get 22, then you would take that and multiply it by 25 to get 550. Hope this helps!

A scale model of a house is 1/10 the size of the actual house. One of the bedrooms in the house is 16 feet long. Which expression will help you find the length of the same bedroom in the model?

Answers

yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees

Determine if the two triangles are congruent.

Answers

Answer:

sas

Step-by-step explanation:

vertical angle stuffs

I believe the answer is Side angle side ;)

Given the expression below, identify its factors.

3a + 4b– 7c - 12

Answers

Answer:

i dont think you can solve this because  

The expression is not factorable with rational numbers.

there are no like terms

math help me pls now now

Answers

Answer:

14/1

Step-by-step explanation:

16/3 –5/4

(16*4–5*3)/12

49/12

1 4/1

Answer: 4 1/12

Step-by-step explanation:

Hope this helps!

3
Gürkan bisikletiyle birinci gün 3.1 km, ikinci gun 4.5 km ve puncu
gun 4.25 km yol almıştır Gürkan üç günde toplam kaç km yol aims
tir? Tahmin ediniz Tahmininizi işlem yaparak kontrol ediniz.

Answers

tahmin etmek için yuvarlama yapmak gerekir 3,1=3 4,5=5 4,25=4,20 hepsini toplarsak 12,20

Model the unknown number problem by writing an
algebraic expression. Then complete the statements.
Juan doubled his workout time.
Replace the words 'workout time" with.
The word "doubled" means
The correct algebraic expression is

Answers

Answer:

Model the unknown number problem by writing an algebraic expression. Then complete the statements.

Juan doubled his workout time.

Replace the words “workout time” with.

✔ the variable w

.

The word “doubled” means  

✔ multiplied by 2

.

The correct algebraic expression is  

✔ 2w

.

Step-by-step explanation:

Answer:

Model the unknown number problem by writing an algebraic expression. Then complete the statements.

Juan doubled his workout time.

Replace the words “workout time” with.

✔ the variable w

The word “doubled” means

✔ multiplied by 2

The correct algebraic expression is

✔ 2w

Step-by-step explanation:

A sum of money is divided between Mohan and Sohan in the ratio 5:7 . If Sohan's share is ₹665, find the total amount.​
please help me fast.

Answers

Answer:

1140

Step-by-step explanation:

7u-> 665

1u->95

7+5=12

12u->1140

what kind of number is e?

a.) integer
b.) rational
c.) natural
d.) irrational

Answers

Answer:

c.natural

Step-by-step explanation:

The number e , sometimes called the natural number, or Euler's number, is an important mathematical constant approximately equal to 2.71828.

e is C. natural

explanation: free points

Write a similarly comparing the three triangles in the diagram

Answers

Answer:

ΔBCE similar to ΔECD similar toΔBED

Step-by-step explanation:

ΔBCE similar to ΔECD similar toΔBED

Write each ratio in three different ways based on the table. Party Mix Makes 8 Cups 3 cups pretzels 3 cups bagel chips 1 cup cheese crackers 1 cup peanuts

Answers

I need the table
To answer

help i dont understand how to do this the question is "Put your answer in decimal form."

Answers

Answer:

x = 2.5

Step-by-step explanation:

Hypotenuse ² = opposite ² + adjacent ²

(x + 4)² = x² + 6²

x² + 8x + 16 = x ² + 6²

x² + 8x + 16 - x² = 6²

8x + 16 = 36

8x = 36 - 16

8x = 20

x = 20/8

x = 2.5

What is the solution of the system of equations? Enter the solution as an ordered pair (use decimal rounded to the nearest hundredth if necessary)

=32+54−2+8=−25

Answers

32+54=86-10=76-25= 51

what's
[tex](4 \sqrt{2} ) {}^{2} [/tex]

Answers

Answer:

32

Step-by-step explanation:

(4√2)^2=4^2×(√2)^2

=16×2

=32

Solve the system of linear equations by elimination x + 2y = 13 --x+y=5​

Answers

Answer:

{x,y} = {1,6}  Have a great day

Answer: welp its already answred

Step-by-step explanation:

Steve studies math for 7/8 of an hour and history for 2/3 of an hour. How many hours did he study?

Answers

Answer:

The answer is 1 13/24 hours or 1 hour, 32.5 minutes

Step-by-step explanation:

Find a common multiple of the denominators 3 and 8, which would be 24.  Convert the fractions:

7/8 x 3/3 = 21/24.

2/3 x 8/8 = 16/24

Add the two numerators = 37/24 or 1 13/24.  

1/24 of an hour is 2.5 minutes, so 13/24 is 32.5 minutes.

The answer is 1 13/24 hours or 1 hour, 32.5 minutes

help me plz !!!!!!!!!!

Answers

Step-by-step explanation:

Since y = x + 3

Substitute the value of y for each one into the equation

1. y = 4

4 = x + 3

4 - 3 = x

x = 1

2. y = 8

8 = x + 3

8 - 3 = x

x = 5

3. y = 5

5 = x + 3

5 - 3 = x

x = 5

Hope you got it

A lumberjack needs to climb a tree to place a satellite tower in the tree top in the woods. The satellite signal needs to reach a horizontal distance of 3500 meters along the ground. If the angle of elevation from the farthest distance along the ground that the satellite reaches to the satellite in the tree is 18 degrees, what is the radius of the satellite signal? Round your answer to the nearest meter.

Radius of the satellite signal = meters

Answers

Answer: I use clickcaculators.com ;)

Step-by-step explanation:

which of the given values will make the inequality n-93>175 true?

n=82
n=105
n=268
n=300
n=312

Answers

Answer:

n = 300 and n = 312

Step-by-step explanation:

n - 93 > 175

n > 175 + 93

n > 268

Therefore only the two last answers are are possible n values (n has to be more than 268, not equal)

The two numbers 300 and 312  will make the inequality n-93>175 true which are correct option (D)300 and (E)312.

What is inequality?

Inequality is the defined as mathematical statements that have a minimum of two terms containing variables or numbers is not equal.

Given inequality as:

n - 93 > 175

n > 175 + 93

n > 268

Therefore, n must be greater than 268 and not equal.

Hence, the two numbers 300 and 312  will make the inequality n-93>175 true.

Learn more about inequalities here:

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