Calculus 1 - Trigonometric identities question!! Help!

[squance]

I'm having issues with this question...

Simplify the expression tan(x)/(1-tan^2(x))

and another question...

Simplify the expression sin(x)cos(2y)+cos(y)sin (2x)

Thanks

[Neobeo]

Simplify the expression tan(x)/(1-tan^2(x))

Notice how it looks very similar to the tan double-angle formula.

Simplify the expression sin(x)cos(2y)+cos(y)sin (2x)

This one I didn't manage to simplify. Looks similar to the compound angle formula for sin, and yet the arguments are different, so I don't think it can be simplified.

[squance]

Meh...i still don't get it
Anyways
Thanks for looking at it anyways
I try to look at the textbook and stuff
(I hate maths sooo much!! especially trig

[Neobeo]

Hint (for the first one):

The double angle formula for tan is as follows:

[gta007]

As
and
 
=
=
=

That's all I got up to. I'm sure one of the maths whizzes will be able to help you. 

YAY! I know how to use latex now.