SOLUTION: How to find the exact value of cos(arctan(-5/3)) by using a reference triangle?

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Question 1060017: How to find the exact value of cos(arctan(-5/3)) by using a reference triangle?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
How to find the exact value of cos(arctan(-5/3)) by using a reference triangle?
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Tangent = y/x
terminal point is (3,-5) in Q4
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r = sqrt(x^2 + y^2) = sqrt(43)
cos = x/r = 3/sqrt(34) = 3sqrt(34)/34