Plotting multiple graphs on the same plot

I need to plot multiple plots on the same graph for different values of z and indicate the maximum value:

For z = 1, 2, 9, 77

y = sin(8*x+pi) + 2*x^2/3 + z*3

How to do that?

Answer 1

[KSSV]

x = linspace(0,2*pi) ; 
z = [1, 2, 9, 77]' ; 
y = sin(8*x+pi) + 2*x.^2/3 + 3*z ;
plot(x,y) ;
legend('z=1','z=2','z=9','z=77')

Read about hold on

[Amy Topaz]

x = linspace(-4*g,4*g);
y = [0.01*g 0.2*g 0.6*g g];
Hx = (1/pi)*(atan(((g/2 + x)./y) + atan((g/2 - x)./y)));
Hy = (-1/2*pi)*(log((g/2 + x).^2 + (y).^2./(g/2 - x).^2 + (y).^2));

plot(x, Hx, 'g-v', 'LineWidth', 2)
xlabel x1 
grid minor
title ('y1 = 0.01*g')
ylabel Hx1
legend('y=0.01g','y = 0.2g','y = 0.6g','y = g')

How to rectify this?

[KSSV]

You need to transpose y.

x = linspace(-4*g,4*g);
y = [0.01*g 0.2*g 0.6*g g]';
Hx = (1/pi)*(atan(((g/2 + x)./y) + atan((g/2 - x)./y)));
Hy = (-1/2*pi)*(log((g/2 + x).^2 + (y).^2./(g/2 - x).^2 + (y).^2));
plot(x, Hx, '-v', 'LineWidth', 2)
xlabel x1 
grid minor
title ('y1 = 0.01*g')
ylabel Hx1
legend('y=0.01g','y = 0.2g','y = 0.6g','y = g')