I agree they are algebraically identical, but I read that you are defining m = R1/R2 and n = R3/R4. If so, I did not arrive at the same answer because I am using m = R2/R1 and n = R4/R3 like Studiot. I may have punched in the wrong numbers.

The two expressions shown will give the same result however you choose m and n. However, if you're expecting to get the same result as equation 1 in the app note, the choice will matter. You need to re-read Studiot's post to unravel that issue; My purpose was to show that the only error in equation 1 of the app note was the upside down R2/R1 in the parentheses, and that there is not a missing term.

 

As a matter of interest have you been able to copy and paste any formulae or have you had to redraft them?

I have been experimenting with a new LaTex writer. I drafted the formulae in this and copy/pasted them into the thread, but have not been able to do this for anything from thread posts themselves.

 

I haven't had any trouble copying Latex out of the posts.