A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modelling.

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Modelling: Use Newton's law to write down an equation for the position $x$ of the mass.

Here is the background for the question: Consider a one-dimensional frictionless spring-mass system, where the forces acting on the mass $m$ at position $x$ are the forces of gravity $F_g =-mg$ with ...
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Is Principal Component Analysis applicable to this type of situation?

I'm trying to model the response of ant populations to pheromones in this way: The ants are simulated as Self Propelled Particles with internal energy. They undergo acceleration due to their internal ...
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40 views

SEIR model need help solving first order linear ODE

I've recently been working on simulating an SEIR (susceptible, exposed, infected, recovered) project for an endemic disease using matlab solving via Euler's method. I have taken a picture of the ...
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Determinate parameters of queue theory problems

I have this exercises: In a service station car wash , the information we have indicates that cars come to be served in FIFO discipline , according to a Poisson distribution with a mean of 4 per hour ...
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1answer
22 views

Parabola properties assumptions

I am trying to model projectile trajectory but I'm having some trouble. I didn't realise parabolas are this complicated... I have some assumptions that I would like to be clarified. If I specify a ...
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2answers
30 views

Parabola describing projectile motion.

I am trying to create a function that will generate a parabola that describes projectile motion. Here are my inputs: The starting x-y coordinate of the throw The initial x-y velocity vector. I ...
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Mathematical Modeling [closed]

Consider the following model (exponential model + harvesting) \begin{eqnarray*} \frac{dP}{dt} & = & rP-h \\ P(0) & = & P_0 \end{eqnarray*} Find an explicit formula for the solution ...
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25 views

Questions about Disease Model

A non-fatal infectious disease divides a population into two groups: normal or ill. Assume that the average number of contacts that each ill individual has with normal individuals is $a$ multiply the ...
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1answer
26 views

Discrete Dynamical Systems & Credit Card Debt: How to solve for payment

I have the following problem, taken out of Giordano, Fox, and Horton's A First Course in Mathematical Modeling: Your current credit card balance is $\$12,000$ with a current rate of $19.9\%$ per ...
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36 views

Lotka-Volterra equations modified

Okay, so I'm just learning about the Lotka-Volterra and the question I have regards the following model: $dx/dt = x(1-y/2)$ $dy/dt = -y(1 - (x/0.8) + (x^2)/4)$ I need to state what term has been ...
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37 views

Interpretation of a model

$$ \frac{dx}{dt}=ax(x-b)(1-x)-\frac{xy}{1+cx}$$ $$\frac{dy}{dt}=-ey+\frac{xy}{1+cx}$$ Make a apropriate interpretation of this model. What I thought are: $\frac{dx}{dt}\ \& \ \frac{dy}{dt}$ are ...
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8 views

Indicate whether each of the following equations is linear or nonlinear.

Indicate whether each of the following equations is linear or nonlinear. If linear, determine the solution; if nonlinear, find any steady states of the equation. $x_n=(1-\alpha )x_{n-1}+\beta x_n$ ...
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80 views

A mathematical abstraction of colours?

Does any formal system exist built upon the mechanics of Additive Colour Theory? Additive Colour Theory is the description of the behaviour of the visible spectrum of light as it combines-the ...
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16 views

Assume we have a system of weights and springs. Find the equilibrium displacement. [closed]

Assume we have a ceiling in which spring $c_{1}$ and $c_{2}$ are attached to. $c_1$ is connected to $m_1$ and $m_1$ is connected by spring $c_{3}$ to mass $m_2$. $m_1$ also has a spring $c_4$ that ...
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Model a dynamic co-variance matrix update with the Kalman Filter

I've previously posted a question regarding the dynamic update of a co-variance matrix and got the answer, that my problem could be solved with a Kalman Filter (KF). After reading and largely ...
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1answer
27 views

Critical points of quadratic forms

Let $A$ be an $n\times n$ symmetric matrix, let $b$ be an $n$-vector, let $c \in \mathbb{R}$ and set $Q(x) = 1/2 x^T Ax-x^T b+c$. Prove that $x_0$, defined as a solution to $Ax_0=b$ is a critical ...
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24 views

find the maximum

I'm stuck in this problem (Instructions and my work is showed on the picture below) I just don't know what to do right after find the values of D, to prove that the maximum of F(D) is attained at the ...
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25 views

Modeling Question: Finding a Fit for the form W=kl(g^2)

I have a modeling question on my assignment that I am unsure about. I am given a set of points $W, l,$ and $g$. I have to find some $k$ for the data to optimally fit $W=klg^2$. At first, I tried ...
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22 views

Lotka-Volterra coordinates transformation

I would like to ask the following: Given a Lotka-Volterra predator-prey system, \begin{align} & \frac{dx}{dt}={\alpha}x-{\beta}xy \\ & \frac{dy}{dt}=-{\gamma}y+{\delta}xy \end{align} , with ...
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58 views

Lotka-Volterra First Integral and Fixed Point

I have the following problem that I am dealing with, quite a long time, I must say. Let us assume that we have a predator-prey, Lotka-Volterra system given to us by: \begin{align} & ...
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Assume two springs with constant $c_1$ and $c_2$ are based in the following scenarios. Figure out the masses for equal displacement [migrated]

More specifically I am to figure out what masses $m_1$, $m_2$ will produce equal displacements $x_1$ and $x_2$ Scenario 1: When the two springs are hung from separate supports Scenario 2: With one ...
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1answer
42 views

Differential Equation - Blood Alcohol

Let C(t) be the concentration of alcohol in a person's bloodstream. We propose a mathematical model which states that, once a person stops drinking alcohol, C decreases at a rate that is proportional ...
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Seems like too many prey get consumed in a standard predator-prey model?

The following equation is a generic differential equation modelling the change in number prey per year in a predator prey model - $\frac{dN}{dt} = rN(1 - \frac{N}{K}) - aPN$ $N$ is the number of ...
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27 views

Determining probabilities Markov Chain

If I have a Markov Chain $X_0, X_1, X_2 \dots$ that has a transition probability matrix $ \textbf{P} = \matrix{~ & 0 & 1 & 2 \cr 0 & 0.3 & 0.2 & 0.5 \cr ...
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98 views

Modelling Concentration

I'm currently doing a research project that involves modelling E. Coli growth in a wetland. The data I've been given is the E. Coli mass concentration ($mgC/L$) at various times throughout the two ...
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For the three measurements b=0, 3, 12 at times t=0, 1, 2 find the best parabola y=C+Dt+E$t^2$

So I know how to do least squares regression using matrices to solve for Ax=b. I simply do $A^TAx=A^Tb$. However I don't really know how to account for the second power in a typical parabola ...
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1answer
19 views

What is the least squares solution given a line passes through original and following points?

So I am looking for the line y=Dt through the origin that fits the data y=4 at t=1, y=5 at t=2 and y=8 at t=3. This is what I have done so far. I know the three equations that are supposed to be ...
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26 views

Write the system of equations describing the populations in this system…

In a closed ecosystem, we have that Frogs,represented by $F(t)$, eat fleas, represented by $f(t)$, and the fleas eat fungus, represented by $g(t)$. Assuming that fungus grows at rate A, fleas eat the ...
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1answer
54 views

Model a chemical phenomenom

I have a chemical phenomenon to model for my research. I'll try to be clear while explaining my problem. I created little molecules (let's call them "emitters"), which emit a signal. When the ...
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75 views

What is the process of nondimensionalizing an equation?

Question: I need to scale time by $\frac{1}{I}$ and species by $P$ for the following equation $\frac{dS}{dt}=I(1-\frac{S}{P})-\frac{ES}{P}$ where P - Size of the source pool of species on the ...
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1answer
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Random Variable Modeling

I am trying to understand how to model a random variable. So using a biased coin with $P(Head) = q$. If I am to generate a random variable $Y$ that is equally likely to be either a or b depending on ...
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1answer
16 views

Finding the minimum value of $1/2 (x_{1}^2+x_{2}^2)-x_{2}b_{2}$

I am trying to find the minimum value of the following: $1/2 (x_{1}^2+x_{2}^2)-x_{2}b_{2}$ I know this is equal to: $1/2 ([x_1 x_2] Id [x_1 x_2]^T )-[x_1 x_2] [0 b_2]^T$ To find minimum we have to ...
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What is the proper name of a model that takes as input the output of another model?

Thanks in advance for the help. I am writing a paper and for the life of me can't remember the proper term for a model that works as follows. rawData -> model1 -> outputModel1 -> model2 -> ...
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1answer
23 views

Online resources for Mathematical Modeling

I'm taking mathematical modeling this semester in college and usually there are resources online to read examples and see another point of view but I'm not able to find it for this class. Can anyone ...
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1answer
28 views

Calculate migration probability matrix from distances matrix

Imagine the world-wide human populations as a series of interconnecting populations. The distances between any two populations is given by the following kind of matrix $$ \begin{matrix} ...
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51 views

How many additional crews should be brought in to minimize the cost of an oil spill?

An oil spill has fouled $200$ miles of Pacific shoreline. The oil company responsible has been given $14$ days to clean up, after which a fine will be $10000$ \$/day. The local cleanup crew cleans $5$ ...
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76 views

Linear algebra of state space representation won't be linear (superposition theorem)…

After answering a question about calculating the state space representation of a circuit with 3 sources in it (the circuit is there), I had a doubt - while checking, it became clear there is something ...
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What is the correct term for the equations which comprise a mathematical model?

I have a mathematical model constructed by myself and my supervisor. In writing my report do I refer to the equations that make up this model as "constitutive equations", or is there another term ...
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22 views

Modeling predator/prey pursuit behavior?

I want to program a model of predator/prey pursuit behavior on a 2D topographical map (not predator/prey diff. eq. model!), primarily for fun, but I'd love to know if there's any literature or ...
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34 views

Modeling Forced Oscillations Resonance Given from Second Order Differential Equation (2.13-3)

My answer to this problem does not agree with the text's answer: $y=sin(t)-3cos(t)$ Problem to solve is to find the steady state oscillations of the vibrating system governed by the following ...
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Saturation Modeling in ODE45

I have a machine with an arm that can move in a linear one dimensional way. There are 3 limits on the arm: The arm has boundary for its location $(x_{min},x_{max})$ The arm has limit on its velocity ...
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2answers
68 views

Math theories in Game Theory

What are all the mathematical theories in Game Theory? I have taken Mathematical Modelling, including: application of linear systems, matrix operations, inverse of matrix, leontif input-output model, ...
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Positivity of compartments in epidemiological model

Given the following dynamical model (system of ODEs): \begin{array} $ \frac{dA}{dt}=\Lambda-\mu A-\beta(C+D+E+F)\frac{A}{N}-\tau(B+D)\frac{A}{N} \\ ...
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Arrange soccer fixtures with correct home - away alternation for each team

I am trying to do as the title says. I have 10 teams in the same group. Every team must play the rest once each but each of them will always alternate home and away. This means that if they play at ...
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Matrix representation from a linear function

I'm studying an opinion formation model [1] where the main rule is: $p^{(t)}_i = \frac{p^{(0)}_i + \sum_{j \in N(i)} w_{i,j} p^{(t-1)}_j}{1 + \sum_{j \in N(i)} w_{i,j}}$ Now, I'd like to represent ...
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39 views

Help me find the function behind this data?

I have a function $f(x, y)$ and I have another (non-mathematical) algorithm capable of inefficiently generating the exact same results as in in a 'brute force' manner. Since I have been able to find ...
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Applications (“in everyday life”) of graph theory

EDIT another idea someone gave me was to consider flows in a network that would not only depend on the node at the beginning and at the end of a vertice but also about the vertice itself, like a ...
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102 views

Problem in game theory related to traffic networks

I have learnt game theory for a short period of time and I am not familiar with multi-player non-zero sum games. Here is a problem from my book which I am stuck: In this road network below each of ...
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23 views

A prove for information restoration with 2 schedules that delete information

What kind of mathematics or technique do I need to use the following? Just pointing me in the right direction is also helpful as I love mathematics but I am not so good at it. It's a problem I have ...
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Understanding mathematical syntax in SO(3) - Part II

In a paper I found in internet there is a relation about mapping a matrix into a vector and viceversa. One question has been already kindly answered here, but since I'm new to this kind of syntax I ...