function [res] = f(x)
n = length(x);
for i = 1:n
    if ((x(i) >= -0.2*pi) & (x(i) <= 0.2*pi))
        res(i) = 5;
    elseif ((x(i) >= 1.8*pi) & (x(i) <= 2.2*pi))
        res(i) = 5;
    elseif ((x(i) >= -2.2*pi) & (x(i) <= -1.8*pi))
        res(i) = 5;    
    else res(i) = 0;
    end
end 