Hi fouad,
Where is that first lecture the link shows?
Also, that lower case 'v' in Vam(t) = (Vc+Kam*Vm(t))cos(2vfct) is supposed to be 'pi' right? So it is:
Vam(t) = (Vc+Ka*m*Vm(t))*cos(2*pi*fc*t)
right?
You might be able to graph this if you label the Y axis as "Vc" and "Ka*Vm" or something like that to show where those appear as cos() is periodic.
Also, you are saying that the peak to peak max is 0.4 volts and peak to peak min is 0.25 volts?
Can we see that "first lecture"?