# 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.

1,858 questions
Filter by
Sorted by
Tagged with
31 views

### Trying to fit a model to “incomplete” data

Suppose the following dataset $\mathcal{D}=\{z_1,z_2,...,z_{80}\}$, was obtained by taking measurements on a natural phenomenon that follows the law: $z=f(x,y)=ax^2+by+c$, where $a,b,c \in \mathbb{R}$....
16 views

### Pandemic spread simulation learning subject [closed]

hello im a student from math department, i have a question about my project, pic above is covid 19 spread patern, i need to figuring out the math model of the spread to make a simulation what ...
59 views

### How to quantify fairness of exams?

So I was thinking about how to model exams. I assumed that teacher will give out $N$ problems to study. Due to the nature of exams, one can't have all $N$ problems on the actual exam, let's say ...
27 views

### What is meant with persistence time in stochastic models?

I've been reading about epidemiological modeling using stochastic models (discrete/continuous Markov chains and stochastic differential equations). I've come across the term persistence time multiple ...
21 views

### Is my average chance of death for a cohort correct

I am trying to model a human population. My simulation calculates at 1 day intervals. I want to track my population counts in cohorts of varying sizes (age 0, 1-14, 15-29, etc). The chance of death ...
58 views

14 views

### Plot a stiff system of three first order ODEs in Excel with sufficient accuracy

I want to plot a system of three stiff ODEs (Oregonator model - chemistry). That model describes a chemical oscillator. I do not have much experience with plotting ODEs, neither do I have experience ...
20 views

147 views

29 views

### SIR model - Why does an increase in infectious individuals cause the rate of infectious to recovered to increase?

When looking at dI/dt we have a term gamma*I, this is the rate in which infectious become recovered. Why is this dependent on I, the number of infectious people? Since if you have lots infectious ...
23 views

### Express three-factor product in matrix form

For a small project of mine, I would like to model a phenomenon (impact of mood and opinion on a social network's member). The data I have is stored in square, same-sized matrices. I would like to ...
21 views

### MAPLE and equilibrium points

for example in this example Solving system of nonlinear differential equation in MAPLE I want evaluate the jacobian matrix of the system for each equilibrium point with mapel ?
21 views

### Why is “five-divide method” and “random-divide method” equal in “number guess game”?

set a range like [0,1000)digital, pick one number a like 733. "two-devide-method":First time you choose 500,and the host tells you it is smaller than a.Then you pick 750,next (500+750)/2.until pick ...
31 views

### Josephus Problem from 1 to N

can someone explain to me the recursive soultion of josephus problem I have found many solutions here and in other places but i can't understand it the recursive solution is ...
139 views

### Mathematics system components probability

For mathematics, I have to perform the following exersice. Consider a system consisting of 6 components: C1, C2, C3, C4, C5 and C6. The system works if at least 3 components work and at least 1 of ...
16 views

### Multicollinearity in logistic regression model

Suppose I want to fit a logistic regression model to my training data.However, I know that some of my regressors may be dependent on each other i.e. some of them are functions of common covariates for ...
29 views

### Mathematical modeling for mixtures

A $200$ liter tank contains $100$ liters of pure water. Starting at time $t = 0$, alcohol is pumped into the tank at a rate of two liters per minute. At the same time the well-stirred mixture is ...
20 views

### Initial values for oscillations about a point problem (normal modes)

I have the Lagrangian $L=\frac{1}{2}(\dot{x}^2+\dot{y}^2) -7x^2+2xy-\frac{11}{2}y^2$. So the two equations of motion are $\ddot{x}+14x-2y=0$ and $\ddot{y}-2x+11y=0$. Hence the general solution (by ...
21 views

### Explain using mathematical terms

I have a list of job descriptions that require mathematical models to explain each of them, there are 8 tasks in number and would like explain the tasks to a non-mathematician. The tasks are as ...
27 views

### Simulation of Hard Core Model

i already learned about Hard core Model and i know the steps Using markov chain monte carlo (MCMC) to realise it.But i don't know how to make/do a Simulation of Hard code Model in practice. Can ...
17 views

### Linear Program for Hyperplane Sparation

GOAL: I want create a simple linear programming model that can be used to classify new data based off of a found hyperplane. In this particular case I have two classes and I'm given a data set in ...
26 views

### Different state space models derived from the same differential equation

I hace come accross the book "Robust Adaptive Control" from the authors "Petros A. Ioannou" & "Jing Sun". There is a free PDF version of the book at the webpage of one of the authors if anyone is ...
The quadratic penalty function was not great because we needed $ρ → ∞$ to get an optimal solution, and for finite values of $ρ$ we could get infeasible solutions. The exact penalty solved this issue, ...
I am trying to approximate the area under the curve of $f(x) = \sqrt{x}$ over the integral $1/2 ≤ x ≤ 3/2$. I am so confused on how to use Monte Carlo without the use of a computer program to estimate ...