MATLAB: Derivative firstly x then y

derivative

f(x,y)=(x^28)/(y^2+x^2)+(sqrt(exp(x*y)+abs(-4*y)) take derivative firstly x and the y for f section.

Using symbolic toolbox, you can do it like this

syms x y
f = (x^28)/(y^2+x^2)+(sqrt(exp(x*y)+abs(-4*y)));
fx = diff(f, x); % derivative w.r.t. x
fy = diff(f, y); % derivative w.r.t. y

Output from live script

disp(f)

disp(fx)

disp(fy)

syms f(x) f0(x) f1(x) f2(x) f3(x) R
fun=diff(f,x)==diff(f0,x)+R*diff(f1,x)+R^2*diff(f2,x)+R^3*diff(f3,x)

   syms x y
   f(x,y) = x*sin(y);
   d2fdxdy = diff(diff(f,x),y); % = cos(y)

Another way is:

   syms x y
   diff(x*sin(x*y),x,y);  % = 2*x*cos(x*y)-x^2*y*sin(x*y)