Question: Need a proof with Maple

Hi all,

> deq := Limit((a^(x+h)-a^x)/h, h = 0);

                                      / (x + h)    x\
                                      |a        - a |
                        deq :=  lim   |-------------|
                               h -> 0 \      h      /
> deq1 := a^x*(Limit((a^h-1)/h, h = 0));

                                   /       / h    \\
                                 x |       |a  - 1||
                        deq1 := a  | lim   |------||
                                   \h -> 0 \  h   //
> f1 := (a^h-1)/h;

                                       h    
                                      a  - 1
                                f1 := ------
                                        h   
> limit(f1, h = 0);

                                    ln(a)

I need to prove the last line for the constant "a" beiing any reals positive

Mario