1

close all
clear all

x=linspace(-3,3,1000);
y=linspace (-2*pi,2*pi,500);
[X,Y]=meshgrid(x,y);
Z=abs((cos(X).^3)).*(abs(cos(Y)));

figure(1)
subplot(3,3,[1:3])
meshc(X,Y,Z)
xlabel('X')
ylabel('Y')
zlabel('Z')
colorbar


X=-3;
Z=abs((cos(X).^3)).*(abs(cos(y)));
a_ros=[];
a_mal=[];
for i=1:length(Z)-1
    if Z(i)>Z(i+1)
        a_mal=[a_mal i]
    elseif  Z(i)<Z(i+1)
        a_ros=[a_ros i]

         else
         end
    end


subplot(3,3,[4:6])
plot(y,Z,'b' ,'LineWidth', 2)
hold on
plot(y(a_mal),Z(a_mal),'bd')
hold on
plot(y(a_ros),Z(a_ros),'rd')
legend(['Z=f(X,y), dla Z=2*pi', 'Z_mal', 'Z_ros'])
grid on



a_i1=[];
a_i2=[];
ZZ=Z;
for i=1:length(Z)
    if Z(i)>= 0.5;
       ZZ(i)==10*Z(i).^2;
        a_i1=[a_i1 i];
    elseif Z(i)<= 0.5
        ZZ(i)==Z(i);
        a_i2=[a_i2 i];
    end
end

subplot(3,3, [7:9])
plot(y,Z,'b' ,'LineWidth', 2)
hold on
plot(y(a_i1),Z(a_i1),'bo' ,'LineWidth', 1,...
            'MarkerEdgeColor', 'k',...
            'MarkerFaceColor','y',...
            'MarkerSize', B)
hold on
plot(y(a_i2),Z(a_i2),'bo' ,'LineWidth', 1,...
            'MarkerEdgeColor', 'k',...
            'MarkerFaceColor','y',...
            'MarkerSize', B)