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**woweycowey****Member**- Registered: 2012-10-20
- Posts: 1

If anyone could help with this that would be amazing, im just finding myself stuck.

(sinxcosx)/((cosx^2)-(sinx^2)) = ((tanx)/(1-tanx^2))

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**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,462

hi woweycowey

Welcome to the forum!

I think you mean sin^2 (x) rather than sinx^2 ie.

Anyway start with the left hand side:

Divide top and bottom by

and it comes out straight away.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Sometimes I deliberately make mistakes, just to test you! …………….Bob Bundy

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**zetafunc.****Guest**

Bob bundy's way is the best way since it is only one step. Here is another neat way to do it but it takes a bit longer (it's how I did it though);

I still prefer the one-step method though, haha. So this post is a little redundant...

**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,462

hi zetafunc,

That's what I thought as well to start with. I think the double angle formulas jump out at you.

But I thought the OP might not have met them so I looked to see if I could bypass them. The tan2A formula comes from dividing by cos so I tried that instead and nearly fell off my chair.

Good to offer a choice so not redundant.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Sometimes I deliberately make mistakes, just to test you! …………….Bob Bundy

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