# What does cos(arctan(2)) equal?

$\cos \left(\arctan \left(2\right)\right) = \frac{1}{\sqrt{5}} = \frac{\sqrt{5}}{5}$

#### Explanation:

arctan(2) is an angle whose tangent function$= \frac{2}{1}$

this means that the angle has opposite side of $2$ and adjacent side of $1$

the hypotenuse measures $\sqrt{5}$

cosine of the angle=adjacent side/hypotenuse$= \frac{1}{\sqrt{5}} = \frac{\sqrt{5}}{5}$

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