# Alex Sha

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**Content Feed**

Curve fitting with custom function

It is hard to get stable and unique result for Da125's problem, especially for parameters of "lambda" and "n". refer to the resu...

2 months ago | 0

FItting 3d with fourier

If taking the fitting function as: the result will be: Root of Mean Square Error (RMSE): 0.000481289122874164 Sum of Square...

3 months ago | 1

| accepted

FItting 3d with fourier

Hi, give your data as text format, not a picture just.

3 months ago | 0

PARAMETER estimation of kinetic and adsorbtion constant of langmuir hinshelwood haugen watson model

if want all parameters to be positive: Root of Mean Square Error (RMSE): 0.0035717712315911 Sum of Squared Residual: 0.0003572...

3 months ago | 0

How to obtain model parameters by fitting experimental data to the monod model. monod model.

Refer to the results below: Root of Mean Square Error (RMSE): 1.50437634361661 Sum of Squared Residual: 81.4733345963976 Corr...

6 months ago | 0

| accepted

curve fitting a custom equation

Hi, all, as mentioned by Walter Roberson, the resule I provided above is obtained by using 1stOpt, the biggest advantage, for 1s...

6 months ago | 0

| accepted

I want to solve 2 equations with 2 variables but it cant be solved and the command window shows fsolve stopped because the last step was ineffective

Hi, the result below should be one solution x1: -52.5485799573576 x2: 12.1032014174617

7 months ago | 0

How to solve a system of second order nonlinear differential equations with boundary conditions

Hi, the chart will be given automatically in 1stOpt UI, also you can make chart yourself by using the result data given above. 1...

7 months ago | 0

I need to fits the attached data as in image

Hi, the fitting function "y = p1/(1+Exp(p2+p3*x)+p4*x)^p5" is pretty good for all data set, where y=L, x=T 1: T1-L1: Root of ...

8 months ago | 1

| accepted

Objective function is returning undefined values at initial point. lsqcurvefit cannot continue.

The best results are as below, hard to be obtained since the initial-start values are impossible to be guessed reasonally. Root...

8 months ago | 0

| accepted

Kinetic parameter estimation and initial time setting

Hi, see the results below: Root of Mean Square Error (RMSE): 4.00513564326846 Sum of Squared Residual: 320.822230419589 Corre...

8 months ago | 0

How to include contratins on 1 variables for this nonlinear system of equations?

Hi, refer to the solutions below: 1: x1: 0.415757622422666 x2: 0.321911265108838 x3: 0.0970690621849188 2: x1: 12.98212823...

10 months ago | 0

Fit points and specify the slope at one of the points

Hi, try the function below: y = p1+p2*x^2-p3*exp(p4*x); to ensure the slope being 0 in point of "x=0.985035", should add a con...

11 months ago | 0

solving set of non linear equation

Hi, refer to the results below: phi1: 0.00687835881390378 phi2: 3.07608732711163

12 months ago | 0

Trouble finding solution of unknown variable in difficult integration problem

Hi, there are two solutions as below: 1: h=0.073660616949704 2: h=0.165217787421255

12 months ago | 0

fsolve is not returning the right solutions

Hi, if you think the solutions should be (1,0,1) or (-1,0,1) , then one equation: F(3) = 1 + 2*x2.^2 + x3.^2; should be: F(3)...

1 year ago | 0

Solving lengthy nonlinear complex equations in complex variables

Try to find numerical solutions as below; y1s.realpart: 11.0169967890388 y1s.imagpart: -125.141575853451 y3s.realpart: 7.8197...

1 year ago | 0

Lsqnonlin_Fitting Data

Hi, if possible, please post out your data of each curve, as well as the fitting equation.

1 year ago | 0

How to Fit a line to scatter data on scatter plot?

Hi, Chetan, if you don't mind the length of the fitting equation, refer to follow: x1=Speed, x2=Dp, y=Eff y = b0+b1*x1+b2*x1^2...

1 year ago | 0

Fitting a Custom Sigmoid

Hi，if the fitting function is： 1：y=a1*exp(-a2*exp(x)) Root of Mean Square Error (RMSE): 0.291990919479646 Sum of Squared Resi...

1 year ago | 0

| accepted

Options when drawing using the Curve Fitting tool

Hi, post your data and function in txt format, if possible.

1 year ago | 0

| accepted

How could I do simutanoues parameter fitting for two series experimental data and multiple datasets?

Hi, post your data please, if possible

1 year ago | 0

Using vpasolve to iterate/solve for flowrate in a piping network

refer to the result below: f1: 0.013713131883721 v1: 1.36937309476078 re1: 409175.227518161

1 year ago | 0

Solving set of 5 non-linear simultaneous equations using fsolve

Hi, Anahita, if you don't want complex answers, then there are problems in your eauqtions, here taking second equation as an exa...

1 year ago | 1

| accepted

Deconvolution of Guassian curve

Hi, you may try 4 Gauss Function: The results will be: Root of Mean Square Error (RMSE): 451.21462729511 Sum of Squared Res...

1 year ago | 3

curve fitting toolbox for y=y0.exp((x0/x)^v) where data is known, but y0,x0 and v are unknown constants

Hi, Em, if fit as the function: y=y0.exp((x0/x)^v), then the result will be about： Root of Mean Square Error (RMSE): 9.39279339...

1 year ago | 1

Nonlinear regression with two variables

Hi, Dipon, post your y, T and pH data please, if possible.

1 year ago | 0

How can I solve this system of equation

Hi, VinceUgo, the eqn8 and eqn9 can be combined into one equation, so your problem become a system equation solving with eight e...

1 year ago | 0

Fitting data to an equation with complex part

lsqcurvefit is seneitive to initial start-values since it use local optimization algorithm, same as cftool, there is a GA toolbo...

2 years ago | 0

| accepted

Failure in initial objective function evaluation. FSOLVE cannot continue

You have three equations with three unknown parametrs, but initial start-values, you provide two only (x0=[1 1];), is this your ...

2 years ago | 1