Some coaching on this would be nice.

All I'm working with is a formula sheet with some identities in it.

Any help at all would be greatly appreciated.

Simplify the expression.

cos(2tan-1(x))

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- Aug 31st 2008, 08:08 PMleftyguitarjoeStumped on a trig simplification
Some coaching on this would be nice.

All I'm working with is a formula sheet with some identities in it.

Any help at all would be greatly appreciated.

Simplify the expression.

cos(2tan-1(*x*)) - Aug 31st 2008, 08:19 PMChris L T521
Note that the trig expression takes on the form , where

Recall that

Now let us set up a triangle that represents the angle .

We see that the opposite leg has a value of x, and the adjacent has a value of 1. Thus, the value of the hypotenuse can be found after applying the Pythagorean formula:

Now, let us evaluate the expression:

can be determined from the triangle we constructed.

Thus,

Substitute this into the equation and simplify:

I'll leave the rest for you to do.

I hope this makes sense! (Sun)

--Chris - Aug 31st 2008, 08:25 PMJhevon
- Aug 31st 2008, 08:26 PMleftyguitarjoe
oh, I made a typo that might affect something

cos(tan^-1 (x)) - Aug 31st 2008, 08:28 PMChris L T521
- Aug 31st 2008, 08:28 PMChris L T521
- Aug 31st 2008, 08:29 PMChop Suey
- Aug 31st 2008, 08:31 PMChris L T521
It doesn't change much:

Keep this bit:

Quote:

Now let us set up a triangle that represents the angle .

We see that the opposite leg has a value of x, and the adjacent has a value of 1. Thus, the value of the hypotenuse can be found after applying the Pythagorean formula:

It should be obvious if you constructed the triangle properly

--Chris - Aug 31st 2008, 08:32 PMleftyguitarjoe