If angle A is 45 degrees and angle B is 60 degrees.

Question

Find sin(A)cos(B),
find cos(A)sin(B),
find sin(A)sin(B),
and find cos(A)cos(B)

The choises for the first are:

A. 1/2[sin(105)+sin(345)]
B. 1/2[sin(105)-sin(345)]
C. 1/2[sin(345)+cos(105)]
D. 1/2[sin(345)-cos(105)]

You don't need to give me the answer to all of them. Just help explain at least one, so I can figure out the rest on my own.

Answer 1

choices*

Answer 2

You just need to review your formulas:

http://www.sosmath.com/trig/prodform/prodform.html

and recall that for trig functions, 345° is the same as -15°