Something deal with trigonometry

[johnchau123]

I have tried many time to simplify the following expression but I cannot.

The following two signals are added.
One is A*cos[(ω'+δω)t+θ]
Another is m(t)*cos(ω't)

When this two expression is added with the dc component removed, the expression is

m(t)cos[(δω)t+θ]
where (A >> |m(t)|)

I don't know how to get this result. Can anyone help me on it?
Thank you very much.
John

 

[masadi]

is it simply two signal2 r added or a signal modulation ?

i suspect this is a signal modulation, where A*cos[(ω'+δω)t+θ] is the carrier and m(t)*cos(ω't) is the modulating signal.

try to find some reffrences about signal modulation (esp amplitude modulation)

 

[neils_arm_strong]

I too think that it is modulation.
Otherwise the signals are of different amplitudes and have to be vectorially added.