# Convert an Equation Editor Object back to plain text

Is there a tool that can convert something like this:

which when copied as plain text looks like this: \frac{4}{\pi}\sin\left(x\right)+\frac{4}{3\pi}\sin\left(3x\right)+\frac{4}{5\pi}\sin\left(5x\right)+\frac{4}{7\pi}\sin\left(7x\right)+\frac{4}{9\pi}\sin\left(9x\right)

To this: 4/pi*sin(x)+4/(3pi)*sin(3x)+4/(5pi)*sin(5x)+4/(7pi)*sin(7x)+4/(9pi)*sin(9x)

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berkeman
Mentor
Is there a tool that can convert something like this:
View attachment 266516

which when copied as plain text looks like this: \frac{4}{\pi}\sin\left(x\right)+\frac{4}{3\pi}\sin\left(3x\right)+\frac{4}{5\pi}\sin\left(5x\right)+\frac{4}{7\pi}\sin\left(7x\right)+\frac{4}{9\pi}\sin\left(9x\right)

To this: 4/pi*sin(x)+4/(3pi)*sin(3x)+4/(5pi)*sin(5x)+4/(7pi)*sin(7x)+4/(9pi)*sin(9x)

What format is the source? Is it just a JPEG or BMP picture, or a PDF snapshot? Or something copy/pasted from MSWord? The source format will make a big difference in how difficult the conversion will be, IMO.
it would be an interesting parsing project in a Comp Sci course on Compilers.
Absolutely. It would be a fun project, if the input format was something reasonable (instead of having to do full character recognition from a BMP file as a first step).

jedishrfu
Mentor
I thought the source was just the latex string to convert to a plain text target

A related fun project would be conversion to character graphics:

Code:
              //\\ pi/2
//
// sin(x) dx
//
\\// 0
come in useful source code

This would come in useful in source code comments or markdown where the viewer uses character graphics.

berkeman
Mentor
Oh, oops, I think you're right. I misread the OP to be "convert from this math equation to LaTeX". Sorry, nothing to see here, everybody move along...

berkeman
Mentor
I thought the source was just the latex string to convert to plain text
And yeah, that's a MUCH easier problem to assign in a compiler class.

FactChecker
Gold Member
What about exporting it as a PDF or PNG file and using OCR software? I tried with FreeOCR on the PNG in the OP, but it did not do very well. Maybe better OCR software would do a better job.

FreeOCR converted it to
%si.1.1[x)+% sin(3x)+% sin(5x)+% sin(Tx) + sin[9.\'

Not a good result. But I have seen OCR software do some impressive things.
PS. I just tried a couple of online TEX to TXT converters and they did not work well.

Last edited:
robphy
Homework Helper
Gold Member
Input: \frac{4}{\pi}\sin\left(x\right)+\frac{4}{3\pi}\sin\left(3x\right)+\frac{4}{5\pi}\sin\left(5x\right)+\frac{4}{7\pi}\sin\left(7x\right)+\frac{4}{9\pi}\sin\left(9x\right)

https://www.wolframalpha.com/input/?i=+\frac{4}{\pi}\sin\left(x\right)+\frac{4}{3\pi}\sin\left(3x\right)+\frac{4}{5\pi}\sin\left(5x\right)+\frac{4}{7\pi}\sin\left(7x\right)+\frac{4}{9\pi}\sin\left(9x\right)

produces

4/π sin(x) + 4/(3 π) sin(3 x) + 4/(5 π) sin(5 x) + 4/(7 π) sin(7 x) + 4/(9 π) sin(9 x)

also interesting:

https://mathpix.com/
http://www.i2ocr.com/free-online-math-equation-ocr
http://www.inftyproject.org/en/index.html

Last edited:
Muskyboi and FactChecker
Input: \frac{4}{\pi}\sin\left(x\right)+\frac{4}{3\pi}\sin\left(3x\right)+\frac{4}{5\pi}\sin\left(5x\right)+\frac{4}{7\pi}\sin\left(7x\right)+\frac{4}{9\pi}\sin\left(9x\right)

https://www.wolframalpha.com/input/?i=+\frac{4}{\pi}\sin\left(x\right)+\frac{4}{3\pi}\sin\left(3x\right)+\frac{4}{5\pi}\sin\left(5x\right)+\frac{4}{7\pi}\sin\left(7x\right)+\frac{4}{9\pi}\sin\left(9x\right)

View attachment 266604
produces

4/π sin(x) + 4/(3 π) sin(3 x) + 4/(5 π) sin(5 x) + 4/(7 π) sin(7 x) + 4/(9 π) sin(9 x)

also interesting:

https://mathpix.com/
http://www.i2ocr.com/free-online-math-equation-ocr
http://www.inftyproject.org/en/index.html
This is exactly what I was looking for. Thank you.

BvU
Homework Helper
2019 Award
produces

4/π sin(x) + 4/(3 π) sin(3 x) + 4/(5 π) sin(5 x) + 4/(7 π) sin(7 x) + 4/(9 π) sin(9 x)
For the record: When you hover the mouse over the picture of the equation, extra buttons appear and the one on the right brings up the plain text

FactChecker
Gold Member
The only potential problem with Wolfram's plain text is that it uses the extended character set, so ##\pi## instead of Pi. That is acceptable in many places that you might paste it, but not everywhere.

BvU
Homework Helper
2019 Award
Turns out Excel () accepts ##\pi## as a name, but of course it wants all the asterisks

π 3.141592654 (formulas|create from selection)

=4/π* sin(x) + 4/(3 *π) *sin(3* x) + 4/(5 *π) *sin(5* x)+ 4/(7 *π)* sin(7 *x) + 4/(9* π) *sin(9* x)

does the work an comes up with a value

sysprog and FactChecker