The first choice,
... a. s(t) = ac[1 + μam cos (2πfmt)] cos (2πfct)
has the carrier frequency cos(2πfct) amplitude modulated by the message signal.
The other expressions represent frequency and phase modulation of various kinds.
Answer:
c. (A + B)^2-A^2 + 2AB + B^2
Step-by-step explanation:
Given that:
a.
(A-B)^2 = A^2 - 2AB + B^2
If and only if AB = BA
Then;
(A-B)^2 = (A -B ) (A - B)
(A-B)^2 = A^2 - AB-BA + B^2 (FALSE)
b.
(AB)^2=A^2B^2
on true if any only if AB =BA
(AB)^2= (AB) (AB)
c.
(A+ B)^2 = A^2 + 2AB + B^2
(A+ B)^2 = (A + B) (A+B)
(A+ B)² = A × A + A × B + B × A + B × B
(A+ B)^2 = A^2 + A*B + B*A + B^2
This is true
Answer:
1. A
2. A
3. B
4. C
5. B
I hope this helped!
Step-by-step explanation: