SOLUTION: need help use a sketch to find exact value of the expression. cos(tan^-1 5/4)

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Question 1089349: need help
use a sketch to find exact value of the expression.
cos(tan^-1 5/4)
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
use a sketch to find exact value of the expression.
cos(tan^-1 5/4)
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tan = y/x = 5/4
r = sqrt(x^2 + y^2) = sqrt(41)
cos = x/r = 4/sqrt(41)
= 4sqrt(41)/41
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Could be + or minus. The quadrant wasn't given.