[R] Does inverse function exist in R

[Patrick Wang]

Hi,

I wrote a simple derivative program

(ftest=deriv(y~x^2, c("x"), function(x){} ))

I put (ftest=deriv(y~x^2, c("x"), function(x){} ))(1) which return 2 which
is correct.

however, if I want the output to be 0 and hopefully a new inverse function
can take in
output (2) and return x=1. Can this be accomplished. Maybe output(0) can
return x=0

Thanks
pat