can anybody show me how to simplify: cos(arctan x), im not too sure on how to evaluate that, thanks!

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- Aug 27th 2008, 09:40 PMah-beesimplification of a cos
can anybody show me how to simplify: cos(arctan x), im not too sure on how to evaluate that, thanks!

- Aug 27th 2008, 09:53 PMChris L T521
Try to construct a triangle with an angle represented by

This implies that our triangle has an opposite of length and an adjacent of length . We can now use this to determine the length of the hypotenuse of this triangle.

Using Pythagoras' Theorem, we see that

Thus,

Since and , we see that

Does this make sense?

--Chris - Aug 27th 2008, 10:20 PMah-bee
omg the way u put it makes it look so easy. very easily understandable!