Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [mathematical-modeling]

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.

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. Mathematical models are used not only in the natural sciences (such as physics, biology, earth science, meteorology) and engineering disciplines (e.g. computer science, artificial intelligence), but also in the social sciences (such as economics, psychology, sociology and political science); physicists, engineers, statisticians, operations research analysts and economists use mathematical models most extensively. A model may help to explain a system and to study the effects of different components, and to make predictions about behaviour.

2372 questions
0
votes
2 answers

How I can express this mathematically?

I'm working on a OR project. I have a code which fixes my problem which uses the constraint ((a =< b) or (c =< d) or (e =< f)) = True I need to rewrite this condition as mathematical expression(s) I tried (a-b) * (c-d) * (e-f) =< 0 Which seems…
Halox
  • 1
0
votes
1 answer

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 variables assuming from the Lotka–Volterra…
user3424493
  • 327
  • 3
  • 5
  • 12
0
votes
1 answer

Definition of "Density" in ecological models

in ecological populations models, the standard variable is the density of individuals, i.e. the number of individuals per space unit (area, volume). The meaning of this is intuitively clear to me, but I'm having trouble putting this into rigorous…
kamui
  • 11
0
votes
1 answer

Simplify water salinity equations

I recently became interested in calculating water salinity from conductivity and temperature. I failed to find any theoretical model to how this is done, only empirical models derived from fitting to experimental data. One such model (first Google…
Theodor
  • 245
0
votes
1 answer

How to model a problem to validate/improve an attempt at solving computer programming problem

I have attempted a solution to a beginners programming question which produces what I think is unexpected output. I need a way to validate it and was hoping to do that mathematically. Problem description: Take a stack of coins all heads up.…
Ian
  • 33
0
votes
2 answers

Simpler way to display mathematical model?

I am developing a mathematical model for the power usage (watts) of a computer device against its percentage of CPU load. So far I have: P(x) when x <= 25% = 8.5 + x*0.46 P(x) when 25% > x <= 50% = 20 + x*0.08 P(x) when 50% > x < 75% = 24 +…
DevWithZachary
  • 103
  • 2
0
votes
1 answer

Speed formula and least square approximation

I have some questions about a formula and least square approximation I have 14 information about the speed of a fluid inside a tube, speed, position and standard deviation. I already made a graphic of these information: (Its x:radios and…
user2969054
0
votes
2 answers

Preparation for modeling in grad school

I'm currently a first year grad student in an applied math program. I really love modeling, but everything in my modeling course is flying way over my head. Where can I look for a decent introduction to this subject? We didn't offer the course in…
Emma
  • 43
0
votes
3 answers

Dollar Cost Averaging and Gas Prices

Dollar cost averaging says the if you invest a set dollar amount at the fixed frequency, you will come out better than purchasing a set number of shares at the same frequency. While filling up the gas tank this morning I was wondering if the same…
Scott
  • 109
0
votes
0 answers

Programming C# Navier Stokes Modeling

I just started C# programming Navier Stokes model for 3D visualized compressible fluid liquid/gas properties management of gasket-plate heat exchanger models of my company. In reality, I can't even understand the equations themselves because of…
11thG
  • 1
0
votes
0 answers

Question regarding variable index notation in mathematical modeling

I have a mathematical model, where the following variables are used: $x_i$, $x_{i,i}$ and $x_{i, j}$, $i \neq j$. There is a need to express these variables with just one variable, using a "wildcard" character in the index of the variable that…
E-O
  • 99
0
votes
1 answer

I'm trying to understand the solution to this simple mathematical modelling question

This is an example from Gary Chartrand's "Introductory Graph Theory" (Page 8, Example 1.5). He provides an answer without actually showing the steps or working, and I am unable to figure it out. The statement of the problem is (after editing out…
mathnewb
  • 1
0
votes
0 answers

Math Modeling confusions

In the story Gulliver’s Travels (read the Wikipedia page if you’ve never heard of it), the 6-inch tall Lilliputians imprison and tie up Gulliver. Reasoning that he is 12 times their height, they feed him $12^3 = 1728$ times the volume that an…
Jiajun Li
  • 1
0
votes
1 answer

How do I draw a phase diagram for this system?

The system of equations is as follows \begin{align} \frac{dx}{dt} &= 6x-3x^2-xy \\ \frac{dy}{dt} &= y-x+3xy \end{align} This is a question in my study guide and I cannot figure out how to draw the phase diagram as the first equation seems to be in…
Hannes
  • 1
0
votes
1 answer

Model/estimate the missing values

I have the value of production waste (m3/day) and also the consumption (kwh/day) of some locations. You can see below that I have total information for locations 1 to 10. However, I don't have a consumption value for units 11 to 15. Therefore, I…
Carlo Soares
  • 3
1 2 3
…
11 12