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:

Step-by-step explanation:
<u>Formula Evaluation</u>
Formulas are expressions where a sequence of letters, numbers or symbols have a determined meaning in given system.
Formulas are usually expressed as mathematical operations that connect one or more variables.
The perimeter of a triangle is the sum of the lengths of its sides. Being a,b, and c their sides, then the perimeter has the formula

We are given the values of



Thus the perimeter is


The answer to the first question is B
The second question is B
Answer:
The value of the 8 in the front is 800,000 and the value of the second is 80,000. The front value is ten times as big as the second value.
Step-by-step explanation: