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

 Messages: [ Previous | Next ]
 Albert Posts: 282 Registered: 12/9/07
Re: Proving trigonometric identities
Posted: Jan 24, 2009 5:02 AM

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)?

> >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 Albert
1/20/09 Angus Rodgers
1/20/09 Albert
1/20/09 Angus Rodgers
1/20/09 Albert
1/20/09 Angus Rodgers
1/20/09 Angus Rodgers
1/20/09 Guest
1/20/09 Angus Rodgers
1/20/09 Albert
1/20/09 Angus Rodgers
1/20/09 matt271829-news@yahoo.co.uk
1/21/09 Albert
1/21/09 matt271829-news@yahoo.co.uk
1/23/09 Albert
1/23/09 Angus Rodgers
1/23/09 Angus Rodgers
1/23/09 Passerby
1/23/09 Dave Dodson
1/24/09 Albert
1/24/09 Angus Rodgers
1/24/09 Albert
1/26/09 Albert
1/26/09 Driveby
1/26/09 Albert
1/26/09 A N Niel
1/27/09 Albert