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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 24, 2009 5:02 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Jan 24, 8:37 pm, Angus Rodgers <twir...@bigfoot.com> wrote:
> Don't you mean a lower quadrant III or IV (assuming they are numbered
> anticlockwise, starting from the positive quadrant, at the top right)?

Yes; I made a mistake!

> >So then there are solutions to the
> >equation, aren't there? and why/why not?

>
> I'm a bit bleary-eyed, but it certainly does look to me as if (b) is
> equivalent to sin x = -3/4, which has one solution for 180 degrees <
> x < 270 degrees, one solution for 270 degrees < x < 360 degrees, and
> no other solutions in the range indicated. (You'll need a calculator
> to find the approximate values of x.)


I agree: assuming sin x = -3 /4 is a step that one should get to (or
take the inverse cosec early on), x = 229, 311 degrees to the nearest
degree.


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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