Answered
Need to rectify error in my matlab code given below
I want to get a plot of dn/dt versus t. syms t mu=2500*(10^-4); %cm^2*V^-1 * s^-1 R = 0.318; eta=377;% ohm N=3.681; %refind...

2 years ago | 0

Answered
Using Runge Kutta to solve second-order differential equations with two degrees of freedom
I don't understand from your code if you want to perform a parameter study for 1000 different values of omega or if you want to ...

2 years ago | 0

Answered
Cannot get fmincon to work
clear close clc format long %% Variables dp = 11.6; taup = 3710e-6; dn = 2; taun = 371e-6; Jl = 50e-3; ni = 9.696e9; ...

2 years ago | 1

| accepted

Answered
I continue to get this error and can't figure out how to fix it, Unable to perform assignment because the size of the left side is 1-by-4 and the size of the right side is 1-b
If you take the derivative of a polynomial, the degree of the resulting polynomial is one less than the degree of the original p...

2 years ago | 0

Answered
coupled differntial equation using ode45
G = 1; Na = 1; xstart = -1; xend = 1; nx = 51; x = linspace(xstart,xend,nx); solinit = bvpinit(x, [0;0;1;0]); sol = bvp...

2 years ago | 1

| accepted

Answered
coupled differntial equation using ode45
syms y mu0 G Na U(y) T0(y) eqn1 = diff(mu0*diff(U,y)) == G; eqn2 = diff(T0,y,2) + Na*mu0*(diff(U,y))^2 == 0; conds1 = [U(-1)=...

2 years ago | 0

Answered
Using tabular data for Curve fitting of function z = f (x, y) with incomplete values of z. These blank z (i, j) automatically takes zero values and this is a problem
green = [5 5 5 5 5 4 4 4 4 1 1 1]; blue = [5 10 15 20 25 5 10 15 20 5 10 15]; yellow = [455 322 261 205 169 410 306 246 191 25...

2 years ago | 1

| accepted

Answered
Numerical method of the "fimplicit" function
Since you can specify a mesh density in x- and y- direction, my guess is that the function is simply evaluated on X x Y. Sign ch...

2 years ago | 0

Answered
My roots don't match example roots when solving routh criterion
syms K s p = s^3+9*s^2+12*s+15+3*K; solve(p,s,'MaxDegree',3) var2 = vpa(ans); var = subs(var2,K,-1)

2 years ago | 0

| accepted

Answered
Interrupt a while loop with functions if it takes too long
Is there a way of timing the iteration during its execution and break it? No. You could go into the function and time certain o...

2 years ago | 1

| accepted

Answered
How to solve the system of time dependent coupled PDE's?
ode23t seems to work for high Reynolds numbers. In case ode23t fails (e.g. for the low Reynolds number regime), I recommend the ...

2 years ago | 1

Answered
Problem with my gamma_water values not giving me the correct pressure using fsolve
Look at the curves and see what's happening. Your first equation has two solutions while your second has none: DelH = -1* (-917...

2 years ago | 0

Answered
An absolutely ascending sequence
x = 0:10; all(diff(x)>0)

2 years ago | 0

| accepted

Answered
Find zero of simple monotonic function where the independent variable can only be integer
If you know a lower integer value xl and an upper integer value xu with y(xl)*y(xu) < 0, you could do a binary search starting f...

2 years ago | 0

Answered
Model simulation Code for SEIR
seir_simulation() function seir_simulation() % Parameters beta = 0.3; % Effective contact rate without control sigma = 1/5; ...

2 years ago | 0

Answered
using loops and arrays to solve for variables in equations
You mean this ? x=zeros(5,1); vis=zeros(5,1); %strain rate epsUse=1e-14; Puse=1e9; PARAMS.R=8.314; %ideal gas constant %d...

2 years ago | 0

| accepted

Answered
How to use Matlab to find a pressure in a temperature and density spreadsheet using the nearest density value.
%Generate artificial data t = linspace(10,30, 25); p = linspace(1, 20, 20); [T,P] = ndgrid(t,p); d = exp(-((T-20).^2+(P-10)....

2 years ago | 0

Answered
Kolmogorov-Smirnov (KS) Test
From the documentation: h = kstest(x,Name,Value) returns a test decision for the one-sample Kolmogorov-Smirnov test with additi...

2 years ago | 0

Answered
Solving the hub location problem
You set % Renewal of population population = offspring; and offspring has only size 1x100 instead of 1x186. Thu...

2 years ago | 1

| accepted

Answered
Why does the value of tolerance stop at n=2 (third value of the iteration) within the while loop?
Maybe you mean tol = 1e-7 instead of tol = exp(-7) ? However: It's correct that MATLAB quits the while-loop after three val...

2 years ago | 1

Answered
Minimization linprog constraint no feasible solution
The last equality constraint says that you want 0*x1 + 0*x2 + 0*x3 + 0*x4 + 0*x5 + 0*x6 + 0*x7 + 0*x8 = 6.6, thus 0 = 6.6 ... ...

2 years ago | 0

| accepted

Answered
4th order Runge Kutta Method Differential System
Note that COne and CTwo are given in muF - thus they should be prescribed as 1000e-6 in your code, I guess. COne = 1000e-6; C...

2 years ago | 0

Answered
Error using odearguments Vector Length issue
s3 = s(3) s5 = s(5) instead of s3=(s) s5=s(4)

2 years ago | 0

| accepted

Answered
Newton Forward difference method
Three coding errors: % Confirmed case Sample data points (x, y) data = [ 1, 88; 2, 49; 3, 47; 4, 8; 5, 34; 6, 762; 7, 98; 8, ...

2 years ago | 0

| accepted

Answered
integral using "int" function
Your code to produce g1, g2 and g3 does not matter. You don't get analytic expressions for the antiderivatives of g1, g2 and g...

2 years ago | 0

Answered
Ode23 is not outputting solutions at the times I specified between t0 and tf in tspan=[t0, t1, t2..., tf]
If you use the "soln" structure as result, ode23 only respects start and end point from your tspan vector. After the integrator...

2 years ago | 0

| accepted

Answered
f(x) = x^2/3(3-x^2)(x-4). How do I enter this function in MATLAB?
Replace c = solve(fx); by c = solve(fx*x^(1/3)==0,'Maxdegree',3);

2 years ago | 0

Answered
Problem with integration: there is a pole on a contour
In the usual sense, your integral does not exist. But you can compute its principal value: syms z syms t real f = (z^2+3*z+2...

2 years ago | 2

Answered
Integral2 seems to substitute non-scalar values of variable into integrand. Why?
"integral2" usually calls the function to be integrated with matrices of the same size for t1 and t2 to make the necessary funct...

2 years ago | 2

| accepted

Answered
error when using lsqnonlin to function containing fzero function
"K" is a vector because "fraction" is a vector. Thus the "y" you compute in "denaturationfun" is a vector. But "fzero" cannot so...

2 years ago | 0

| accepted