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Topic: Proving trigonometric identities
Replies: 32   Last Post: Jan 27, 2009 1:59 AM

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Albert

Posts: 282
Registered: 12/9/07
Re: Proving trigonometric identities
Posted: Jan 20, 2009 3:11 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Jan 20, 6:40 pm, Angus Rodgers <twir...@bigfoot.com> wrote:
> On Mon, 19 Jan 2009 23:31:43 -0800 (PST), Albert
>
> <albert.xtheunkno...@gmail.com> wrote:

> >On Jan 20, 6:25 pm, Angus Rodgers <twir...@bigfoot.com> wrote:
> >> Are you familiar with the algebraic identity (a + b)(a - b) = a^2 - b^2?
>
> >Yes I am - are you implying the following steps:
> >(cosx)^2 = (1 + sinx)(1 - sinx)
> >..``..``.= 1 - (sinx)^2
> >?

>
> Yes, I was, but you hardly need to know what I was thinking,
> because the result is clear now, isn't it?



I don't think that it's a proof though. Please enlighten me.


Date Subject Author
1/20/09
Read Proving trigonometric identities
Albert
1/20/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/20/09
Read Re: Proving trigonometric identities
Albert
1/20/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/20/09
Read Re: Proving trigonometric identities
Albert
1/20/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/20/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/20/09
Read Re: Proving trigonometric identities
Guest
1/20/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/20/09
Read Re: Proving trigonometric identities
Albert
1/20/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/20/09
Read Re: Proving trigonometric identities
matt271829-news@yahoo.co.uk
1/21/09
Read Re: Proving trigonometric identities
Albert
1/21/09
Read Re: Proving trigonometric identities
adder
1/21/09
Read Re: Proving trigonometric identities
matt271829-news@yahoo.co.uk
1/23/09
Read Re: Proving trigonometric identities
Albert
1/23/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/23/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/23/09
Read Re: Proving trigonometric identities
Passerby
1/23/09
Read Re: Proving trigonometric identities
Dave Dodson
1/24/09
Read Re: Proving trigonometric identities
Albert
1/24/09
Read Re: Proving trigonometric identities
Angus Rodgers
1/24/09
Read Re: Proving trigonometric identities
Albert
1/26/09
Read Re: Proving trigonometric identities
Albert
1/26/09
Read Re: Proving trigonometric identities
Driveby
1/26/09
Read Re: Proving trigonometric identities
Albert
1/26/09
Read Re: Proving trigonometric identities
A N Niel
1/27/09
Read Re: Proving trigonometric identities
Albert
1/20/09
Read Re: Proving trigonometric identities
adder
1/20/09
Read Re: Proving trigonometric identities
victor_meldrew_666@yahoo.co.uk
1/20/09
Read Re: Proving trigonometric identities
Dave Dodson
1/20/09
Read Re: Proving trigonometric identities
Pfsszxt@aol.com
1/20/09
Read Re: Proving trigonometric identities
Albert

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