SOLUTION: How do i evaluate cos(-7pi/2) and tan(15pi) with exact answers only?

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Question 596871: How do i evaluate cos(-7pi/2) and tan(15pi) with exact answers only?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
How do i evaluate cos(-7pi/2) and tan(15pi) with exact answers only?
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cos(-7pi/2)
Add 2pi repeatedly until the result is positive.
-7pi/2 + 2pi = -3pi/2
-3pi/2 + 2pi = pi/2
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cos(pi/2) = 0
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tan(15pi)
Subtract 2pi repeatedly until <= 2pi
--> tan(pi)
= 0