Hi;
In this form, I do not think of a way to store it in RPN format. Anyway, you can change it from C = (A^2 + B^2)^1/2 to (A^2 + B^2)^1/2 - C. In this case, one of the solutions (expect many) would be:
Consider C and B already stored in the current directory
LEVEL1 LEVEL2
« -> A
«
B B
SQ (x^2) B^2
A A B^2
SQ (x^2) A^2 B^2
+ B^2+A^2
.5 .5 B^2+C^2
^ (y^x) (B^2+A^2)^.5
C C (B^2+A^2)^.5
- (B^2+A^2)^.5 - C
»
»
Given A in the stack, this program returns the expression value. If it returns zero, you have a root. To automate the process, it's necessary to use the ROOT command, and you'll need an extra procedure.
Hope it helps. (I did not check this info, I have neither the manuals, nor the calcs in hand now. Maybe there are some errors)