Posted by **mtd** on Wednesday, April 9, 2008 at 2:06pm.

sorry, another I can't figure out

Show that (1-cot^2x)/(tan^2x-1)=cot^2x

I started by factoring both as difference of squares. Would I be better served by writing in terms of sine and cosine? Such as:

[1-(cos^2x/sin^2x)]/[(sin^2x/cos^2x)-1]=(cos^2x/sin^2x)

- Math (Trig) -
**Reiny**, Wednesday, April 9, 2008 at 2:36pm
I don't think your equation is an identity,

I tried several angles and the Left Side is not equal to the Right Side.

Check your typing.

In general, I try to prove these type of identities by changing everything to sines and cosines, unless I can recognize one of the common trig relationships.

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