Using FROOT recursively on the HP-71?

[Ángel Martin]

Well, it's resisting the first attempts - I guess it'll require more finesse than what I was trying so far...

One question though - I'm not sure I understand the syntax of the FNROOT used as a function of a continuous variable. I assumed FNROOT will return just *one* value (the first root found within the interval), but what does FVAR mean in the statement below:

DEF FNF = X*X+Y*Y <or whatever your function is>
DEF FNY (X) = FNROOT (Y1, Y2, FNF (X, FVAR ) )

Unfortunately I don't have the Math Pack manual, and neither can I figure it out (aging brain, no doubt).

Cheers,
ÁM