function sentpaaaftenen()
syms x y
a=0.1; b=0.2;
f=5*x*y*exp(-x^2-5*y^2);
fx=diff(f,x);
     fy=diff(f,y);
     fab=subs(f,{x,y},{a,b});
     fxab=subs(fx,{x,y},{a,b});
     fyab=subs(fy,{x,y},{a,b});
     [x,y]=meshgrid(-2:0.1:2,-2:0.1:3);
mesh(x,y,5*x.*y.*exp(-x.^2-5*y.^2))
hold on
z=(x-a)*fxab+(y-b)*fyab+fab;
mesh(x,y,z)

