Proof for tan4φ through Euler formulae

vik121

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Hi everyone, so this is an example from my Calculus for physicists exam that I can't seem to solve.

Prove using Euler's formulae that:

[MATH]tan4\varphi = \frac{4tan\varphi - 4tan^3\varphi}{1-6tan^2\varphi+tan^4\varphi}[/MATH]
It is also written as a hint that we should regard the reciprocal value of the expression, and that tanx=sinx/cosx.

I've done two similair examples which with cot2φ and tan2φ using euler's formulae, but both of those included a specific trick in a specific part of the example which makes it hard to intuitively guess where'd it go in this one.
I have found a couple of videos doing the proof for this expressions, but none of them are using the euler formulae.
 
Hi everyone, so this is an example from my Calculus for physicists exam that I can't seem to solve.

Prove using Euler's formulae that:

[MATH]tan4\varphi = \frac{4tan\varphi - 4tan^3\varphi}{1-6tan^2\varphi+tan^4\varphi}[/MATH]
It is also written as a hint that we should regard the reciprocal value of the expression, and that tanx=sinx/cosx.

I've done two similair examples which with cot2φ and tan2φ using euler's formulae, but both of those included a specific trick in a specific part of the example which makes it hard to intuitively guess where'd it go in this one.
I have found a couple of videos doing the proof for this expressions, but none of them are using the euler formulae.
Euler was a prolific mathematician (understatement). He derived many formula. Can you please state the formula that you think that you are being asked to use?
 
Oh, sorry, I thought I had written it.
The formulae meant are the
[MATH]cosx=\frac{e^{ix}+e^{-ix}}{2}[/MATH][MATH]sinx=\frac{e^{ix}-e^{-ix}}{2i}[/MATH]
 
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