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If x is acute and tan x = 5, then find cos x.

 Jun 14, 2020
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So let x equal of one of the acute angles in a 90 degree triangle. Since \(tan=\frac {opposite}{adjacent}= \frac {5}{1}\), and by the Pythagorean Identity, we can find that the sides are 5,1, and \(\sqrt 26\). Therefore, cos x = \(\frac{adjacent}{hypotenuse}\)\(\frac{1}{\sqrt 26}\) = \(\frac{\sqrt 26}{26}\).

 Jun 14, 2020

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