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## #1 2010-10-17 03:00:20

123ronnie321
Member
Registered: 2010-09-28
Posts: 128

### Trigonometry

sin(a) + sin(a+b) + sin(a+2b) +.....+ sin (a+nb) = ???

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## #2 2010-10-17 03:56:29

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Trigonometry

Hi 123ronnie321;

This is provided that n = 0,1,2,3,4,...

There is a formula for that particular sum. I used a computer instead.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #3 2010-10-17 03:56:56

G_Einstein
Member
Registered: 2008-08-30
Posts: 124

### Re: Trigonometry

sorry didn;t had time to write it correctly but I think that the result is correct  notice that cosa=cos(a)   ans sinna=sin(na)  but I had not time to wrote it .....

Last edited by G_Einstein (2010-10-17 03:58:24)

Se Zoti vete e tha me goje,se kombet shuhen permbi dhe,por SHqiperia do te roje,per te,per te luftojme ne.
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