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# Alex Sha

Last seen: Today Active since 2019

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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

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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

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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

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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

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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

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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

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Options when drawing using the Curve Fitting tool
Hi, post your data and function in txt format, if possible.

1 year ago | 0

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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

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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