formula node error

[WCR]

Error using formula node with non-linear fitting VI.

I am using LV 2011 on windows XP.
Using Nonllinear Curve Fit.vi.  I have used this before successfully.I am using the "formula string" instance of this polymorphic VI.  When I run my program using the formula string "b0+b1*x", it runs fine and give sensible results.  When I use the formula string "b0+b1*x+A1*x^2" I get the error message "Error -23083 has occurred at an unknown location. Analysis: Bracket problem at the end."

Attached screenshots show part of the block diagram that wrorks (lv0.bmp) and ppart of the block diagram that does not work (lv1.bmp).

Thank you.

[Dennis_Knutson]

You are doing a bit exclusive or with the ^ operator. If you want exponentiation, you need to use **.

[WCR]

Thank you Dennis. It turns out the "caret" ("^") operator is OK here, and is raising a number to a power, as desired.  The problem was that I used an uppercase letter in a variable name.  Not allowed!  Nor can variable names have have two letters, although that wasn't the problem in my example. (It was a problem in some of my other attempts.)