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Questions tagged [nonlinear-functions]

A function that does not validate the additivity or homogeneity properties is characterized as non-linear.

In mathematics, a linear function (or map) f(x) is one which satisfies both of the following properties:

  • Additivity or superposition: f(x + y) = f(x) + f(y)
  • Homogeneity: f(alpha * x) = alpha * f(x)

A function that does not confirm the above is characterized as non-linear.

374 questions
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Dealing with big sized array in c programming

I am working on nonlinear differential equation. What I was doing is to average up the positions over 100 different values of initial conditions. I used odeiv in gsl. For each initial values, the time range is 4*10^7. However, the program kills,…
supergentle
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solve a system of nonlinear equations in matlab

I'm trying to solve 4 nonlinear equations in matlab. i wrote a code using fsolve but it failed to proceed, and wrote another one using solve but after 4 hours of running without a result I stop it myself. I dont know what else i can use to solve…
parisa
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Can't get real solution with sympy.solve

I tried sympy.solve to solve an nonlinear equation system. It gave me a complex solution set. Then I tried this equation system in matlab, and got a real solution set which I think is correct, because this is actually a geometry problem and I…
shyuu
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Finding the roots of a nonlinear equation using C++

What method would I use to find the roots of f(x) = 5x(e^-mod(x))cos(x) + 1 ? I have being trying the durand-kerner method but I can't get it to work. Are there any easier ways of doing it? Here is the my code using the durand-kerner method #include…
Ca01an
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Having problems with ODEINT in python

I am relatively new to Python and trying to use it to solve a second order nonlinear differential equation, specifically the Poisson-Boltzmann equation in an electrolyte. phi''(r) + (2/r)*phi'(r) = (k^2)*sinh(phi(r)) Essentially it describes the…
David Gillespie
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How to solve a non linear equation involving integral in MATLAB

I am trying to solve the following system of equations in MATLAB: S = solve([real(integral(@(r)sqrt(qn2(x+iy,r)),0.6,1)/pi) == 1, imag(integral(@(r)sqrt(qn2(x+iy,r)),0.6,1)/pi)== 0], [x, y]) Where qn2 is a function handle. MATLAB has trouble…
OmniJames
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Solving nonlinear FEM in MATLAB

I try to solve a heat diffusion problem on tetrahedral finite elements with nodal heat sources, which depend on the solution vector, in MATLAB. The nonlinear equation system looks like this: BU' + AU = q(T) with B being the heat capactiy matrix, A…
Daniel Düsentrieb
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Newton's method roots on Matlab

I am not so much experiences with Matlab. I just need it for the sake of solving some lengthy non-linear equations. Instead of using fzero, I wanna use Newton-Raphson's to solve the equation. newton.m file contains the following code. function [ x,…
India Slaver
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Not able to use `fzero()` function in Matlab

I am new to Matlab. I am trying to solve a non-linear equation using this inbuilt Matlab function called fzero() but it's not giving me the results. The main file goes like A = 5; B = 6; C = 10; eq = equation (A, B, C); fzero(@(x)eq); The other…
India Slaver
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Roots of a non-linear equation using Matlab

I am using Matlab to find the roots of a non-linear function. The equation is lengthy and I have used another .m to save the function, the code for which goes like function x_c = f_x_c(s,H,VA,Lo,qc,EA,NF,Sj,Fj) if (s < 0) || (s > Lo); disp('The…
India Slaver
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MATLAB: fsolve function

I am trying to practice with 'fsolve' and have not figured out fully what's been going on with the following code. Can anyone please shed some light on it? function N=productivity1(N,Ac,Aw) global Thetac Thetaw tau a…
london
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Use Matlab/Maple to find roots of a nonlinear equation

I am having difficulty in finding roots of a nonlinear equation. I have tried Matlab and Maple both, and both give me the same error which is Error, (in RootFinding:-NextZero) can only handle isolated zeros The equation goes like -100 +…
India Slaver
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MATLAB Solving non-linear algebraic equation

I am trying to solve a vectorial equation where vectors are in polar form the equation is 100*exp((pi/3)*j) + 200*exp(x(1)j) - 300(x(2)*j) - 315 = 0; as you can see there is two unknowns in this equation x(1) and x(2) and since it's a complex…
MChawa
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r- Adding multiple unrelated nonlinear fuctions (not fitted) to a scatterplot

I have made a scatter plot of raw data. The equation for the quantile lines takes the form of y=10^a*x^b. (The equation for the quantile was log transformed and meaningless to the audience when viewed). How do I add this form of a function to the…
user4245054
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Two equations two unknowns, non-linear Mathematica

I am having trouble obtaining values using the NSolve or Solve features in Mathematica for two non-linear equations in two unknowns. I am sure there must be a method to go about this, but am not sure what it is. Here is where I encounter the…
Ralphie
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