1
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0answers
19 views

Simple differential equation modelling question.

The question is: A chemical dissolves in water at a rate equal to 10% of the amount of undissolved chemical per hour. At time $t$ hours the amount of undissolved chemicalis $x$ grams. Initially the ...
0
votes
1answer
28 views

Linear Optimization: Minimum Cost Network Flow Model

Consider the directed graph G=(V,A) where each directed arc (i,j) $\in A$ has associated with it a distance $d_{ij}$. Formulate a minimum cost network flow model that will identify the shortest paths ...
1
vote
1answer
33 views

What are the Routh Hurwtiz Criteria for 3$\times$3 Matrices?

The Criteria I know (for dynamical systems) is... The eigenvalues of a matrix are guaranteed to be negative if Tr($J$)<0 and det($J$)>0, where $J$ is the Jacobian of some 2 dimensional dynamical ...
0
votes
0answers
10 views

Difficult transition between homogenous and heterogeneous paramaters

I'll start with an example in queueing theory. Lets assume a M/D/k queue, i.e. a queue with $k$ servers where arrival rate is determined by a Poisson process. We try to find the mean waiting time. ...
1
vote
0answers
33 views

Why does the price term in Vega disappear for a European call option?

In my course, I have been asked to prove a number of statements about "the Greeks" from the Black-Scholes model for pricing a European call option with no dividends and a strike price of $K$. One of ...
0
votes
1answer
63 views

nullclines with variables

I know how to solve nullclines, the following link is very helpful http://mcb.berkeley.edu/courses/mcb137/exercises/Nullclines.pdf However I don't understand how to solve equations that have only ...
4
votes
0answers
228 views

Modelling a Water Rocket. Requires Some Validation and Help. ( WARNING : Extremely Long but Interesting Post )

Good day people of math.stackexchange.com This is a pet project that I plan to use to convince my Prof that I would rather try something similar to this than to do the prescribed project. Edit : ...
1
vote
0answers
43 views

Suggest a random phenomenon for which the Galton-Watson branching process might provide a reasonable model.

Suggest a random phenomenon for which the Galton–Watson branching process might provide a reasonable model. Be clear about the random variable beingcounted (Zn) and the interpretation of the notion of ...
0
votes
0answers
28 views

Variable Growth Rate and Logistic Model

I am reading my notes and I am unable to understand what the following means or how it can be interpreted. A logistic Model is given by the equation \begin{equation} ...
-1
votes
2answers
104 views

Linearize Non-linear Model

How can I linearize a nonlinear model using $$y=Ax^b$$ and $$y=A\ln x+B$$ I couldn't find much online using the above methods. The notes are taken from a class in Models in Applied Mathematics ...
-1
votes
2answers
54 views

Modeling with First Order Equations [closed]

A ball with mass 015kg is thrown upward with initial velocity 20m/s from the roof of a building 30m high. There is air resistance of magnitude v^2/1325 directed opposite to the velocity , where the ...
2
votes
0answers
41 views

Calculating heterozygosity of a population as size increases (combine growth and genetic drift equations)

I am working on a assignment to program a genetic drift simulator and include population growth. My program works fine as far as I can tell, and I have the not unexpected result that in the time I am ...
0
votes
1answer
110 views

Are my linear program equations correct?

Here's the problem: "An electronics company has a contract to deliver 21,475 radios within the next four weeks. The client is willing to pay 20 dollars for each radio delivered by the end of the first ...
0
votes
2answers
44 views

What are the limitations of modelling a piano sound with the 'play' option of the software Wolfram Mathematica?

'Play' is an input availabe on Wolfram mathematica, which shows how a wave would sound and I am asking myself what the limitations of this input are, in what aspects it does not represent 'real' sound ...
4
votes
1answer
146 views

Simple 2D Voronoi Diagram Question with 3 Points

This is a HW question for the course MAT480 (Mathematical Modelling I) at Athabasca University. I'm taking this distance course for credit in order to graduate sooner. Having a hard time putting all ...
1
vote
1answer
73 views

What is the possible equation for this problem?

I am a programmer, I am in a situation that requires a mathematical equation. I just hope to know the final equation that solves the problem (step by step solution is not necessary). Of course I will ...
1
vote
1answer
976 views

Linear Programming Inventory Problem

I'm still trying to get used to the nature of these problems and I'd appreciate some further explanation. ...
3
votes
2answers
780 views

Financial Linear Programming Problem

I'm very new at linear programming and I'm trying to figure out a way to approach this problem below: ...
0
votes
3answers
65 views

What would the equation of this graph be?

Is this a sine graph? How would I model this graph?
1
vote
1answer
80 views

Can you please help me model this curve?

I have no idea how to model this curve. Can someone please help?
1
vote
0answers
18 views

simplifying equations from model

I'm using the community land model (CLM) to do some university work and I'm trying to understand some of the equations that go into the model, one example is: $$ ...
1
vote
1answer
2k views

Examples of types of mathematical models

I am a student currently doing a course on modelling and simulation. I came across the classifications of mathematical models and studied that they can classified as static or dynamic, deterministic ...
2
votes
1answer
202 views

How to classify equilibrium points

I have the two differential equations: $$\frac{dN_1}{dt} = N_1(2 - N_1 - 2N_2)$$ $$\frac{dN_2}{dt} = N_2(3 - N_2 - 3N_1).$$ I worked out the equilibrium points to be at $N_1 = 0, \frac{4}{5}$ and ...
2
votes
2answers
96 views

Linear Models - Regression Analysis

As a student learning Applied Regression Analysis, I come from a background with very little information about this topic. I understand that given $y = \beta_0 + \beta_1x_1 + \epsilon$ $E(y\mid x) = ...
2
votes
0answers
130 views

Check my solution - Modelling of a spring with Differential Equation

I am doing some work with differential equations. I have solved the following problem but am uncertain if I'm doing it correctly. Could someone look over it for me and check if I'm doing something ...
2
votes
0answers
44 views

Need some help on petri nets?

Here's the question: $\qquad$ How do we go about doing this ? I have very little knowledge on petri nets. Can someone answer it for me ? (And regarding the program part , just give me an idea on ...
0
votes
1answer
203 views

Problem with continuity of a piecewise function

I am stuck with a homework problem which is about the modelling of tumor growth by ODEs. The function $A(t)$ is the amount of drugs in the patients blood. During some intervals (namely, $(n,n+\tau)$, ...
0
votes
3answers
1k views

Calculating time of flight of object (Mechanics - horizontal elevated launch)

I need help with the following question: A smooth spherical object is projected horizontally from a point of vertical height H = 25.78 metres above horizontal ground with a launch speed of u = ...
0
votes
2answers
1k views

Calculating initial velocity (horizontal launch)

I need help for the following question: In a long jump event, an athlete jumps a horizontal distance of 7.56m. The athlete was airborne for 3.04 seconds. The acceleration due to gravity is taken as ...
1
vote
1answer
117 views

Solving $4t+{2\over t-3}+{2\over3}=0$ [duplicate]

Possible Duplicate: How would I rearrange this equation to make the subject $t$? The scenario is as follows: A sub-atomic particle is travelling in a straight line through a tubular ...
1
vote
1answer
155 views

How would I rearrange this equation to make the subject $t$?

$$s(t) = 4t + \frac2{t-3} + \frac23$$ where $s$ represents the position of either particle in the tubular cloud-chamber measured in centimetres, while $t$ represents the time in nano-seconds. It's ...
0
votes
1answer
222 views

Question Based On Mathematical Modeling [Applied Functions]

An example of a calulus book reads: A rectangular storage container with an open top has a volume of $10$ m . The length of its base is twice its width. Material for the base costs $10$ per ...
0
votes
1answer
132 views

Competition Models

Need help getting started on this homework problem and I am really lost. The notes given on this subject are really sparse and I haven't found anything online that was useful. Sorry about the lack of ...
1
vote
0answers
114 views

How to know if the Fourier Transform is surjective

I am studing if I could modell a function using LUTs (ROMs) for a electronic digital design. I have two functions, a FFT and other function, S. S function system recive as input the output of the FFT ...