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#1 2018-10-02 09:24:54

zahlenspieler
Member
Registered: 2018-04-12
Posts: 6

Sine and cosine

Let r be a real number; and J^2=-1. Then


and

Thus

In my proof I didn't use any extension of the exponential function to complex numbers; but just some (very rough) estimates for

etc.

Last edited by zahlenspieler (2018-10-02 23:29:24)

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#2 2018-10-02 22:43:52

Mathegocart
Member
Registered: 2012-04-29
Posts: 1,941

Re: Sine and cosine

Could you fix your LaTeX? The first two LaTeX codes were not rendered properly.


The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
He will be sorely missed.

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#3 2018-10-03 01:13:18

zetafunc
Moderator
Registered: 2014-05-21
Posts: 2,210
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Re: Sine and cosine

Hi zahlenspieler,

I have fixed your LaTeX.

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