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8 votes
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Finding an exponential curve

The short answer is that if you fit the Log of your data using Fit, where the model is a linear function of ...
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6 votes

Finding an exponential curve

Without additional information it isn't possible to verify the book solution! For second part of your question try ...
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0 votes

How to estimate Taylor series expansion from the function values

Update Thought my original answer would give another view into why it's "just a problem with precision," in Silvia's words, that would make it easy to see why. Apparently I was wrong: ...
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1 vote

How to estimate Taylor series expansion from the function values

Use the function ND: If I understand correctly you have a numerical function and you want its m first Taylor expansion coefficients. These coefficients are the r'th derivatives of the function at x=0 ...
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2 votes

How to estimate Taylor series expansion from the function values

The Taylor series is accurate around the expansion point. Therefore it does not make sense to fit over an extended region. Rather using the difference quotient and "Limit" seems more ...
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3 votes

How to estimate Taylor series expansion from the function values

Without a minimal working example from OP, I suspect this is just a problem with insufficient precision. To demonstrate what I mean, let me use Exp[-(x/10)] for ...
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0 votes

How to bound a set of data points from above?

Since the data not always looks contain the original {0,0},we consider to use ConvexHullMesh ...
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4 votes
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How to bound a set of data points from above?

See if this does what you want: ...
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3 votes

How to restrict FindDistribution to real-valued distributions

I agree with OP that this is some kind of bug, in Version 12.3 at least. Compare: With exact parameters: ...
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2 votes

How to restrict FindDistribution to real-valued distributions

If we ignore that feeding just 3 data points to a black box function that estimates a distribution is rarely recommended, there is a simple workaround that avoids obtaining complex numbers. Look at ...
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2 votes

How to restrict FindDistribution to real-valued distributions

I think decimals cause it. The following works well. d = TruncatedDistribution[{1, 7}, Rationalize[FindDistribution[{3, 3.4, 3.6, 4}], 0]] CDF[d, 5] // N ...
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8 votes

NonlinearModelFit's fit is atrocious

There are a few issues with the fitting. Some issues are issues with fitting in general (i.e., no matter what software package is used) and some issues are caused by you. First the issues caused by ...
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12 votes
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NonlinearModelFit's fit is atrocious

Nonlinear optimization problems almost never just magically work without a push in the right direction. This is especially true for problems with multiple local minima like this one. You need to give ...
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14 votes

NonlinearModelFit's fit is atrocious

We need to select another fit function( shift the function Sin[a*x] to Sin[a (x + p)] + q) ...
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1 vote

Find a fitting function for a strongly monotonically falling function

Here's my tip: when exploring trends like these, use different ways to plot the data to get a good idea of what you're dealing with. For example: ...
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5 votes

Find a fitting function for a strongly monotonically falling function

The OP says The problem is that I could not find a suitable first guess function One option is to leave the guesswork to Mathematica and use FindFormula ...
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8 votes
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Find a fitting function for a strongly monotonically falling function

Following the useful hint in @H.Zhou's comment try ...
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4 votes
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How to fit experimental data using NonLinearModelFit

Your data data = Import["https://pastebin.com/raw/cLxyZbdy","TSV"]; First of all, as pointed out by @MarcoB and JimB in the comments, your ...
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1 vote

Simultaneous nonlinear fitting of two datasets to two trial functions with shared parameters

Just a side comment around the starting values. For these type of multi-function fits, I usually define my chi-squared merit function and minimise it using NMinimize. For this case the function looks ...
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2 votes

Simultaneous nonlinear fitting of two datasets to two trial functions with shared parameters

Not an answer, but an observation to think further. Seems Angle1 shifted 3 m to right is Angle2 plus litte noise !? ...
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5 votes
Accepted

Simultaneous nonlinear fitting of two datasets to two trial functions with shared parameters

My previous answer dealt more with getting starting values. Once you have good starting values, then MultiNonlinearModelFit works fine. But I do need to give my ...
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5 votes

Simultaneous nonlinear fitting of two datasets to two trial functions with shared parameters

This is an extended comment (as it requires some graphs). Plot your data. Good starting values are your best friends (as mentioned by others). Each dataset of yours is capable of estimating all of ...
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2 votes

fit a time series with a form containing time as a TimeObject

There is a syntax issue that needs to addressed first. You have ...
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6 votes
Accepted

VectorAround problem

Its hard to say if this answers it for you since it seems to be version dependent and my current 12.3 runs error free. But i had these error often before. It got better in 13.1. for me. Essentially ...
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