ok- there were a couple of extraneous steps there, but I still don't see any mistakes...

Posted by Joel on October 21, 2002 at 18:50:56:

In Reply to: I seem to be stuck without an "area" to evaluate. somebody please check... posted by Joel on October 21, 2002 at 18:43:08:

: : Please help me find the area of the region.

: : R={(x,y)| 0<=x<=(2Pi), 0<=y<=(2Pi), [Sin(x+y)Cosy]>=(Sin x) }

: sin(x+y)cos(y) >= sin(x)
: (sin(x)cos(y)+cos(x)sin(y))*cos(y) >= sin(x)
: sin(x)cos^2(y) + cos(x)cos(y)sin(y) >= sin(x)
: cos(x)cos(y)sin(y) >= sin(x) - sin(x)cos^2(y)
: (1/2)cos(x)cos(2y) >= sin(x)(1-cos^2(y)) ignore this one
: (1/2)cos(x)cos(2y) >= sin(x) - sin(x)cos^2(y) ignore this one (here we are again :)
: (1/2)cos(x)cos(2y) >= sin(x) - sin(x)(1+cos(2y)/2
: (1/2)cos(x)cos(2y) >= sin(x) - (1/2)sin(x) - (1/2)sin(x)cos(2y)
: cos(x)cos(2y) + sin(x)cos(2y) >= sin(x)
: (cos(2y))(sin(x)+cos(x)) >= sin(x)
: cos(2y) >= (sin(x))/(sin(x)+cos(x))
: y >= (1/2)arccos(sin(x)/(sin(x)+cos(x))

: which is a bunch of open-ended, roughly vertical, squiggly lines if I'm not mistaken.

: or did I do something illegal with a "zero" someplace?

Follow Ups:

• Re: ok- there were a couple of extraneous steps there, but I still don't see any mistakes... T.Gracken 07:47:55 10/22/02 (3)
  • Re: ok- there were a couple of extraneous steps there, but I still don't see any mistakes... Joel 18:09:14 10/22/02 (2)
    • O.K. I'll rephrase... T.Gracken 21:13:09 10/22/02 (1)
      • Re: O.K. I'll rephrase... Joel 22:03:05 10/22/02 (0)

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