MATLAB: Hello every body, i want to ask you how to derive an equation per a matrix ( 3X3)

Question

the matrix X is:

X=[X11 X12 X13 ; X21 X22 X23; X31 X32 X33]

,the equation P is:

P=a.X11 +b.X12+c.X13+d.X21+e.X22+f.X22+g.X23+ h.X31+i.X32+j.X33

Answer 1

A = sym('X%d%d', [3 3]) ;
K = rand(3,3) ;  % your constants 
B = K.*A ;
iwant = sum(B(:))