how to solve a system of non linear-equations
Hi, I get the solutions below: 1: r1: 0.0136978624480164 r2: -0.0529268624480211 c1: 23794.5028958407 c2: 1043438.64860562 ...

2年弱 前 | 0

No solution found when solving 3 non linear equations
Hi, all, how about the solutions below, from the numerical perspective： 1： x1: -5.21219473201765E21 x2: -0.279500437676178 x...

2年弱 前 | 0

Multiple equations solving in MATLAB
Hi, Golam, post out your problem, we may try.

2年弱 前 | 1

8 nonlinear equations, 8 unknowns - little luck with fsolve/vpasolve
Hi, Alex Tekin, you may try some solvers or software package with the ability of global optimization, i.e. Baron, Lingo, 1stOpt....

2年弱 前 | 1

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Non-linear Multivariate regression using genetic algorithm
The GA toolbox in Matlab is not an ideal tool for curve fitting with the goal of global optimizatiom result. Refer the result be...

2年弱 前 | 0

fminsearch for fitting a function to experimental data
There seem to be two sets of solutions: 1: Root of Mean Square Error (RMSE): 2.45406561689894 Sum of Squared Residual: 78.291...

2年弱 前 | 0

What is "Equation solved,fslove stalled'?
There are two solutions: 1: x1: -0.000499999999999997 x2: -2.28184863820141E-18 2: x1: -2.52247055758755E-18 x2: -0.000429...

How can I find a correct value of the guess for my system of non linear equations ??
it is not easy to get correct initial start values, try to use global optimization algorithm instead of local ones like fsolve, ...

Constrained Global Optimization Problem with MultiStart, GA and HybridFunction using Parallel Processing
the best results: Root of Mean Square Error (RMSE): 69.3464929074478 Sum of Squared Residual: 577072.329427525 Correlation Co...

Failure in initial objective function evaluation. LSQCURVEFIT cannot continue.
Hi，Thaer Ismail， which is your exact fit function: "ydata=1-x1*exp(-(x2/xdata)^x3)" or "ydata=1-x1*exp((-x2/xdata)^x3)" ? if th...

Least Square Curve Fitting, finding the initial start values in lsqcurvefit function in Matlab
if " the second and third number are 0.2 and 0.4.", then the result will be much better: Root of Mean Square Error (RMSE): 0.01...

System of nonlinear equations
Hi，Mahboubeh， the results of your second case are much different with that of your first one, so in second case you use approxim...

How can i calculate five unknown parameters??
There are multi-solutions for Charalampos's problem: 1: iph: -12.4464463252524 io: -889977.402184639 n: -4891.45375599277 ...

Here is the right solution, obtained from 1stOpt: a: -2.38880243947768E-9 b: 0.357245116257183 c: -32.3471147348507 d: -0.0...

change the type of last three equations from (by removing denominator): 6.2975e-11 - (((x(6)^4)*(x(8)^8))/((x(4))*(x(5)^3)*(x(1...

Fslove don't find the right solution
I get the results: 1: q1: 31.25152 q2: -3.3648581278838E-15 q3: -37.1015437789933 2: q1: 31.2515200000001 q2: 1.378921962...

How to solve a nonlinear system of n equations
some results: 1: x1: 1.04727193704753 x2: 2.09481403258296 x3: -3.14176920919256 2: x1: -1.04719783053703 x2: 4.763975200...

Problem in using fsolve
Two of solutions: 1: x1 0.0302626794484622 x2 2.44987629792448 x3 -3.17840769482201 x4 -0.0245615818144686 x5 -0.291871074...

I have two equations that are difficult to solve, so I am using fsolve to get the sol. But while running the program I encountered the error .Please help me or tell other way to solve these equations.
there are two solutions: 1: F1: 0.458069398988435 f1: -1.13829069933547 2: F1: 0.280093672719386 f1: 0.0244403974479464

Why I cannot get a solution for this system?
A set of approximate solutions： lfd: 0.273760301072663 r1d: 0.0994325019367128 l1d: 0.236671205261253 l1q: 0.077183609924249...

i have system of 15 equations and 15 unknown when i use (vpasolve) after 45 minit i have solutions with Warning: Solutions might be lost. [solvelib:​:allvalues​_warning]
Hi, it is easy to get the results below: y1: 4.99999995833333E-5 y2: 0.000199999986666668 y3: 0.0199999966666674 y4: 0.99999...

vpasolve: numeric instability when solving a system of three quadratic equations
The unique stable results are: u: 0.241646208739371 v: -1.29626943837113 w: 2.05462322963176

Fitting Data to a Non-Linear Curve
If don't care the function type, the follow is one: y = p1*(p2^x)*(x+p3)^p4; Root of Mean Square Error (RMSE): 0.0032240913289...

Curve Fit data using FIT
the fit function "myEqn='(-a/(1+exp(c*((x-b)/h).^2)-1))+d'" is not correct, refer to: the function should be: myEqn='(-a/(1+e...

Problem with fsolve: system of 6 nonlinear equations and more
a stable results: thot_membrane 470.276797155953 tcold_membrane 470.271756744994 thot_out -727.941719280904 thot_coolingplat...

Trying to solve a system of equations with 14 equations and 14 unknowns
One result I got: a: 9.16543127083558 d: -3.41610736637613 v: 0.0215111341146459 re: -56206.8082673153 f: -0.00113861533204...

Solution to 8 non-linear equations.
for the case: a1= 4.8994; a2=5.143; a3= 4.09248; a4= 6.264; a5= 3.7584; a6= 2.81184; a7= 5.568; a8=4.176; g1=0.00001; ...

Solving the root of 5 equations with 5 unknowns.
Hi， Kaleb Crook， refer to the below results: x1: 0.0481826850207524 x2: 0.0410231263942099 x3: 0.0404768236956547 x4: 0.0777...

find a function that approximates a given set of data imposing conditions