fun=Function[x,x^2-2] defines a function similar in behavior to fun

In your example above, fvar no doubt means "function variable" or some such. It should have been written as Fun=Function[fvar,fvar^2-2] or as Fun=Function[x,x^2-2]

Thank you both for your answers. But I entered the function module in my first message but somehow that disappeared. I will enter it again

findRoot [expr,{ var,init}, eps ] :=

Module[{ xi=init, fun=Function[fvar, expr ] },

While[ Abs[fun[xi] ] > eps,

xi=N[ xi - fun[xi] / fun'[xi] ];

{var -> xi} ]x^

f[x_ ] : = x^2 -2

findroot [ x^2 - 2, {x,2},0.0001] out {x -> 1.4..}

I do not completely understand the pure function 'fun' From what I learned in previous chapters I translate this (with above example) fun=Function[fvar, x^2-2] . But that is not the correct interpretation.

Why not fun=Function[x,x^2-2]. or something like fun=Function[fvar, fvar^2 -2] ? I really would like to understand how it works

A.Geeraert

Hi Dave,

Thank you for your answer. Paul Wellin has example Notebooks where the given example runs flawlessly , but not with me. Next time I use the Mathematica code as given in the Guidelines.

Best regards Chiel