Question 927605: sin a = 3/5, cos b = 15/17, a and b in Q1
Find sin ( a+b ), cos (a+b)
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! Here's a similar problem.
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cos a = 4/9, a in Q1, and tan b = -5/4, b in Q2.
Find sin (a+b), cos (a+b), tan (a+b)
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sin(a+b) = sin(a)cos(b) + sin(b)cos(a)
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cos(a+b) = cos*cos - sin*sin
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