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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,529

A bit primitive, but what do you think? Works?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 81,704

Hi MathsisFun;

Cool! Can you get it to output in latex if I want it that way? Also how about in addition to the sliders you have size input boxes too.

Here is a problem,

for this one I am getting.

The det(A) is 0 not 3.199999999

Also because the determinant is 0 this matrix is singular, no inverse.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Nice page!

Two things:

- When you click on the cell of a matrix, I think it'd be good if the current contents got highlighted so you can type over them.

- When a result has a big negative number (big in size, so -0.00001 would count) then trying to transcribe the result over to a matrix makes that cell only display "-". The value is stored properly though, so it's just a visual thing.

Why did the vector cross the road?

It wanted to be normal.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 81,704

Hi MathsisFun;

I notice you can directly edit the answer matrix but you cannot store it back into A or B.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,529

Thanks for the feedback! It may take me a while to work on it. First up: the det(A) bug.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,529

OK, got most of your requests done I think:

* determinant now right for "1 2 3 ..." matrix

* there is now a "latex" option for output. Should work inside a math tag

* use Tab key: it selects entire next cell

* input cells text is now on one line (so "-" should stay attached to text)

* output is now not editable (no time at the moment to handle "parsing" text input ... maybe in future)

(use refresh and look for v0.52 at bottom)

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 81,704

Hi MathsisFun;

I am happy. Worked fine. Tried it out on inverting the 5 x 5 Hilbert matrix, this has a condition number of around 500 000 to 1 000 000 ( ratio between the largest and smallest eigenvalue). Numerical stability of your method to invert wasn't bad. Incidentally it got the determinant of the the 5 x 5 Hilbert matrix correct.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,529

That's a mean matrix.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 81,704

Funny thing is I have never seen them used in any application other than for proving how hard they are to invert.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**simron****Real Member**- Registered: 2006-10-07
- Posts: 237

The only complaint I can think of probably doesn't apply to many people here, but if both matrices are 10x10, then B gets cut off.

Linux FTW

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