Posted by **terra** on Friday, September 2, 2011 at 9:31pm.

Simplify by referring to the appropriate triangle or trigonometric identity:

cos(arctan(x))

- math -
**Reiny**, Friday, September 2, 2011 at 9:50pm
sketch a right-angled triangle with some angle Ø

, label the opposite side x and the adjacent side 1

(this way tanØ = x/1 , and Ø = arctan(x/1)

the hypotenuse would be √(x^2 + 1)

and

cosØ = 1/√(x^2+1)

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