# Tagged Questions

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### Chains of approximate numeric equalities

Mathematica considers two numbers equal if "at most their last seven binary digits" differ. For example: ...
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### What does it mean that “there are no significant digits to display”?

So I substitued with the following values in my function T(x,n) and it gave me this red box with the value in the picture. When I hover over it, it tells me that there are no significant digits to ...
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### data fit using second order PDE

I'm trying to find the parameter for second order PDE using data. i don't know what is the error of that, ...
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### What Heads do not have the attribute NumericFunction, but still give True in NumericQ?

The following expressions give True in the NumericQ test: ...
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### Can't get a numerical value for this vector operation

I have written these codes: ...
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332 views

### Matching pair of numbers {a,-a}, where a is numeric

Imagine you have a list of pairs of numbers, such as {{2,-2}, {1,5}, {1,-3},{-3,3}} The task is to reduce the given list to a list of pairs of type ...
57 views

### Determine whether one value is divisible by another [closed]

How do I determine whether one number is evenly divisible by another in the case of large numbers, for example: 52^52 / 52!
271 views

### Center column heading in TableForm

I have a TableForm as follows: ...
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### why i cannot get appropriate number with my custom precision? [duplicate]

why i cannot get appropriate number with my custom precision? In[25]:= N[(1 + Exp[-30])/(1 + Exp[-29.9]), 1000] Out[25]= 1. I expect to see a few digits after 1....
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### Numerical Integration/Function

I have a problem with a function defined numerically through an integral of the form: ...
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### Difference Eigenvector values in mathematica 9 and mathematica 10 [duplicate]

I have the following matrix; ...
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### The problem (time) caused by ?NumericQ

In here, I asked a related (similar) question. Using ?NumericQ seems have slowed down the entire calculation. But I now have a more serious problem: ...
92 views

### Error with numerical summation - how to specify “n choose r”?

I'm trying to do the following sum: NSum[((50000 - x) choose x)*(1/3^15)^x*((3^15 - x)/3^15)^(50000 - x), {x, 1, 4}] But I keep getting an error saying: ...
901 views

### Could I define 0^0 to be 1? [duplicate]

Many occasions, where I need to work numerically with functions. For a variable strictly between 0 and 1, during the optimization, it could become 0.^0 or 0^0, which then become indeterminate. Is ...
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### Speed up numerical optimization (for plotting and solving)?

Briefly speaking, I want to plot a function PIfun[], which its value is based on numerical optimization using NMaximize. It ...
118 views

### Inverse prediction function

I am trying to write a code which learns a data set. Now, I want to know the input value for a given output value. Consider, the following code ...
241 views

### Why does N[Re@f] give complex result?

Consider this code: ...
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Let ...
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### Dealing with square roots [duplicate]

Consider following expression: $$\sqrt{-\left(2 \sqrt{x^{-8/3}-x^{-4/3}+1}\, x^{4/3}+5\right) x^{4/3}+4 \sqrt{x^{-8/3}-x^{-4/3}+1}\, x^{4/3}+2 x^{8/3}+5}$$ In code: ...
67 views

### Eigenvectors inside a maniupulate function

I am trying to make a physics application and it requires that the eigenvectors be taken for a 3x3 matrix. It is my intention that Mathematica never have to deal with the matrices symbolically. ...
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### Why does one Monitor expression work while another fails?

I have a (somewhat involved) function f[x?NumericQ, y?NumericQ] and for some reason it behaves differently when given a Table ...
476 views

### Why is 1. x (Times[1.`, x]) not simplified to x?

This is maybe a silly question, but I could not think of any logical reason why it is not simplified automatically. I was working with a big linear equation system with some constrained inequalities ...
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### Strange NSum behavior for slightly larger number of terms

For some sums, NSum gives me the result nicely for some number of terms, but if I add one more term, it suddenly becomes much slower. I haven't found the minimum example for which this can be ...
205 views

### FindRoot for numerical function and how to search more than one root

I have to find the first few zeros of function for which I have not the analitycal expression. The function is named f in the following code and it is the result of ...
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### Numeric values from transform

How would I create a table of values from a transformation? eg: ...