Select the correct answer.
What is the expanded equivalent of sin(a + b)?
A.
sin a cos b - cos a sin b
B.
sin a cos b + cos a sin b
C.
cos a cos b- sin a sin
D.
cos a cos b + sin a sin b

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?