Trig

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

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.

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asked by Sade
  1. choices*

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    posted by Sade
  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°

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    posted by Steve

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