Сергей Галкин

x=0:30;
i=0:30;
a=0.71.^(i+1);
stem(i,a,'k','LineWidth',2)
set(gca, 'FontName', 'Helvetica', 'FontSize', 12); 
grid on
box off
xlabel('i (samples)')
ylabel('Amplitude')

clear,clc
fun = @root3d;
x0 = [2 2 2];
x = fsolve(fun,x0,optimoptions('fsolve','Display','none'))

function F=root3d(x)
    F(1) = (0.0024*x(1)*(1-x(1))+0.2132*x(1)*x(3)/(1+x(3))-0.0287*x(1)*x(2));
    F(2) = ((-0.0018)*x(2)*(1-x(2))+(-0.0426)*x(2)*x(3)/(1+x(3))+0.0046*x(1)*x(2));
    F(3) = (0*x(3)*(1-x(3))+0.0259*x(3)*x(1)/(1+x(1))+(0.0082)*x(3)*x(2)/(1+x(2)));
end