Find the value of the inverse of a function in some point

[baggepinnen]

Rather than expressing it as a minimization problem, you want to find the root (zero) of

x -> f(x)-y

Example

using Roots
f(x) = x^2
finv(y) = fzero(x->f(x) - y, 1) # set initial guess here
finv(2)

julia> finv(2)
1.41421