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..just wanted to make sure im reading this right..

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- #1

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..just wanted to make sure im reading this right..

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TD

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That is correct.

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[tex] \tanh ix=\frac{\sinh ix}{\cosh ix}=\frac{i\sin x}{\cos x}=i\tan x [/tex]

Therefore

[tex] ix=\mbox{arc}\tanh \left(i\tan x\right) [/tex]

Pick [itex] x=\arctan y [/itex]

So

[tex] i\arctan y=\mbox{arc}\tanh \left(i\tan\left(\arctan y\right)\right)=\mbox{arc}\tanh iy [/tex]

q.e.d.

Daniel.

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