matlab问题，dalao在哪里，55555

Question

Answer 1

直接上代码吧

syms x y 
f = (6*x-x.^2) .* (4*y-y.^2);
dfdx = diff(f,x);
dfdy = diff(f,y);
df2dx2 = diff(dfdx,x);
df2dy2 = diff(dfdy,y);
df2dxdy = diff(dfdx,y);
[x0,y0] = solve(dfdx,dfdy);
x = x0;
y = y0;
A = subs( df2dx2 );
B = subs( df2dxdy );
C = subs( df2dy2 );
delta = A.*C-B.^2;
disp('极值点有 x:')
disp( x(delta>0) )
disp('y:')
disp( y(delta>0) )

结果

极值点有 
x = 3
y = 2