Question: How do you define and use derivatives of a function you define yourself?

Maple people:

The title is the question.  I defined a function in Maple, which works.  I am trying to get Maple to compute its derivatives.  I want to save the derivatives as functions.  Here is a code snippet.  The function itself works.  I have uploaded the worksheet.  Mapleprimes seems to have copied the entire worksheet into this question when I uploaded the worksheet. 

[begin code snippet]

d:=proc(B)
  M:=Matrix(3):
  for i from 1 to 3 do
     for j from 1 to 3 do
      M(i,j):=m(B,i,j):
     end do:
  end do:
 Determinant(M):
end proc:
Warning, `M` is implicitly declared local to procedure `d`
Warning, `i` is implicitly declared local to procedure `d`
Warning, `j` is implicitly declared local to procedure `d`
d(B);
              1                                 
            ------ exp(-3 B) exp(-5 B) exp(-6 B)
            823200                              

                  11                               
               - ----- exp(-3 B) exp(-5 B) exp(6 B)
                 19600                             

                  33                               
               + ----- exp(-3 B) exp(5 B) exp(-6 B)
                 19600                             

                  9                              
               - ---- exp(-3 B) exp(5 B) exp(6 B)
                 1400                            

                  1                              
               + --- exp(3 B) exp(-5 B) exp(-6 B)
                 980                             

                 11                             
               - --- exp(3 B) exp(-5 B) exp(6 B)
                 210                            

                  99                             
               + ---- exp(3 B) exp(5 B) exp(-6 B)
                 1120                            

                 3                            
               - -- exp(3 B) exp(5 B) exp(6 B)
                 80                           


d1:=D(d);
                              D(d)
d1(B);
                            D(d)(B)
d1(0); #doesn't work
                            D(d)(0)
d12dtry:=x->diff(M(x),x);
      d      
x -> --- M(x)
      dx     
d12try(1); #doesn't work
                           d12try(1)

[end code snippet]

Download derivOfFun.mw