function my_first_matlab_script

    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %% askhsh 1
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
        %1 
    a = 2^5/(2^5-1);
    disp(['result 1: ', num2str(a)]); % the result will be displayed only if a is converted to string 
        %2
    a = (1-1/2^5)^(-1);
    disp(['result 2: ', num2str(a)]); % I overwrite variable a
        %3
    a = log(exp(3));
    disp(['result 3: ', num2str(a)]); % I overwrite variable a
        %4
    a = log10(10^5);
    disp(['result 4: ', num2str(a)]); % I overwrite variable a
        %5
    a = sin(pi/6);
    disp(['result 4: ', num2str(a)]); % I overwrite variable a

    
    

    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %% askhsh 2
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    disp('------ askisi 2--------');
    A = [1 2 3]; % grammh
    disp(A);
    B = [3;4;5]; % sthlh
    disp(B); % here I do not need to use num2str because inside disp I have only double (not double+string)
    disp('====  2.1 ====');
    C = A' % instead of disp I do not use ;
    disp('====  2.2 ==== ');
    A = [1 1+i 1-i];
    C1 = A' % ypologizei ton syzygh anastrofo pinaka
    C2 = A.' % correct
    disp('====  2.3 ==== ');
    A = [1 2 3];
    B = [3;4;5];
    C3 = A+B.' % h prosuesh mporei na ginei me 2 tropous
    C4 = A.'+B % edw to .' einai peritto mias kai A, B exoyn pragmatika stoixeia

    disp('====  2.4 ==== ');
    C5 = A.*B.' % pollaplasiazw ta STOIXEIA tou A me ta STOIXEIA toy B. Oi pinakes prepei na einai idias diastashs
    C6 = A.'.*B % dhladh (A.') .* B.  to idio me panw apla to apotelesma einai grammh / sthlh antistoixa


    disp('====  2.5 ==== ');
    C5 = A*B % pollaplasiazw ena 1x3 pinaka me ena 3x1 pinaka 1x3 * 3x1 = 1x1
    C6 = B*A % pollaplasiazw ena 3x1 pinaka me ena 1x3 pinaka 3x1 * 1x3 = 3x3
    C7  = A.'*B.' % idio me C6 

    disp('====  2.6 ==== ');
    A = [1 3; 4 5];
    C8 = A(1,:)
    C9 = A(:,2)
    C10 = det(A) % mono gia tetragwnikous pinakes!!
    C11 = inv(A) 

    % b tropos gia eyresh antistrofoy
    I = [1 0; 0 1]; % monadiaios pinakas
    C12 = A\I; % prosoxh den einai diairesh alla isodynamei me  inv(A)*I = inv(A)


    disp('====  2.7 ==== ');
    % lynoyme to systhma Ax=b dhladh x=inv(A)*b ή αλλιως x=A\b;
    A = [5 -3 2; -3 8 4; 2 4 -9]
    % o A einai 3x3 ara gia na ginei h diairesh prepei o b na einai 3x1
    %3x3 3x1 --> 3x1
    b = [10; 20; 9]
    x = A\b
    % epalh8eush
    d = A*x



    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %% askhsh 3
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    disp('------ askisi 3--------');
    disp('====  3.1 ==== ');
    x1 = -10:0.1:10 % bhma 0.1 gia kalyterh analysh (-10 -9.9 -9.8 klp)
    f1 = exp(-x1/10).*sin(x1);
    figure; plot(x1, f1);
    % bazoyme kai titlo
    title('grafikh parastash synarthshs')
    xlabel('eimai to x');
    ylabel ('eimai to y');
    legend('ki egw eimai h kampylh'); 

    disp('====  3.2 ==== ');
    syms x2;
    f2 = exp(-x2/10).*sin(x2);
    figure; ezplot(x2, f2, [-10, 10]);
    % bazoyme kai titlo
	title('grafikh parastash synarthshs')
    xlabel('eimai to x');
    ylabel ('eimai to y');
    legend('ki egw eimai h kampylh'); 

    % as baloume kai tis dyo kampyles mazi!!
    figure;
    hold on; % xwris auto, 8a panwgrafei h yparxousa kampylh
    ezplot(x2, f2, [-10, 10]);
    plot(x1, f1, 'm--'); % allazw xrwma gia na fainomai.. kai bazw kai diakekommenh grammh gia na mhn krypsw thn allh kampylh
	title('grafikh parastash synarthshs')
    xlabel('eimai to x');
    ylabel ('eimai to y');
    legend('with symbolic variable', 'and without');



    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %% askhsh 4
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    disp('------ askisi 4--------');
    disp('====  4.1 ==== ');
    z = 3+sqrt(3)*j;
    R = real(z)
    I = imag(z)
    disp('====  4.2 ==== ');
    % kata ta gnwsta enas migadikos z = a+jb grafetai ws z=|z|*exp(jwmega)
    % opoy wmeega h efaptomenh ths gwnias tou
    % tropos 1
    platos = abs(z)
    gwnia = angle(z)

    % tropos 2
    platos2 = sqrt(R^2+I^2) % parathreiste oti einai iso me platos
    gwnia2 = atan2(I, R)% parathreiste oti einai iso me gwnia

    disp('====  4.3 ==== ');
    % polikh morfh
    z2 = platos*exp(j*gwnia)
    % parathrw oti z2 = z

    disp('====  4.4 ==== ');
    syms x y;
    z = x+y*j;
    f = (z.^2-3)./(z-1);
    figure;
    ezsurf(x, y, f, [-5 5]);
    xlabel('pragmatiko meros');
    ylabel('fantastiko meros');
    zlabel('synarthsh f');



    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %% askhsh 5
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    disp('------ askisi 5 --------');
    disp('====  5.1 ==== ');
    % me thn xrhsh symbolikwn 
    syms x;
    f = x^3-2*x^2-3*x+10;
    rizes = solve(f, x)

    disp('====  5.2 ==== ');
    % xwris thn xrhsh symbolikwn kai epeidh einai polywnymo!!
    % pernaw ston pinaka toys syntelestes polywnymoy
    p = [1 -2 -3 10];
    rizes2 = roots(p)
    % parathrw oti rizes = rizes2

end