Differentiation of non-linear polynomial

Please the differential part gives giving me empty curly brackets instead of values in this code set.

% Initial x1 and x2
x1 = 5, x2 = 4

% Equations
y1 = (x1-3)^2 + (2*x2 - 8)^2
y2 =(x1-4)^2 + (x2 - 10)^2
%Given y values
y = [5;49]
% First set of y values
yo = [y1;y2]

f = y - yo

A11 = diff(poly((x1-3)^2 + (2*x2 - 8)^2),x1)
A12 =diff(poly((x1-3)^2 + (2*x2 - 8)^2),x2)
A21 =diff(poly((x1-4)^2 + (x2 - 10)^2),x1)
A22 =diff(poly((x1-4)^2 + (x2 - 10)^2),x2)

I was expecting to see this:

or