diff



Hi,

I want to:
1. compute 1 derivative with respect to z of function  F(n,z,c) defined 
by recurence:
f(z,c):=z*z+c$
F(n, z, c) :=
        if n=1 then f(z,c)
         else f(F(n-1, c, z),c)$
diff(F(n,z,c),z);

2. use derivative as a function ( evaluate it for given values):
m(n,z,c):=diff(F(n,z,c),z);

I can do first task but second not.

I have tried:
m(n,z,c):='diff(F(n,z,c),z);
or
expr:'diff(F(n,z,c),z);
m(n,z,c):=ev(expr,diff);
or
google, but still with no effect.

Adam