close all
clear all
t=0:0.01:4*pi;
w=1;
A=4;
y=A*cos(t).*(sin(2*w*t).^2);
yw=y
for i=2:length(t)-1;
    if y(i)>0
        yw(i)=y(i)^2;
    elseif y(i)<0;
        y(i)=y(i);
    end
end
plot(t,y,'r')
xlabel('Amplitude')
ylabel('time')
grid on
hold on
plot(t,yw,'g')
legend('legenda')