MATLAB HELP!

Plot the density as a 3D-surface function of temperature and pressure.

x = t(1,:)

y = p(:,1)

z = d

surf(x,y,z)

xlabel('Temperature (F)')

ylabel('Pressure (psi)')

zlabel('Air Density (lb/ft^3)')

Using the combination of the hold on command and 'plot3' function, add black lines to this plot (given above) that represent densities as a function of temperature for 200 PSI (4th element of pressure array), 500 PSI (8th element of pressure array), and 800 PSI(10th element of pressure array).