May 2nd, 2009, 04:27 PM  #11 
Newbie Joined: Mar 2009 Posts: 16 Thanks: 0  Re: please help...geometry
d1 = distance from point x0y0 to directrix d2 = distance from pointx0y0 to focus is this correct ???? 
May 2nd, 2009, 06:53 PM  #12 
Global Moderator Joined: Dec 2006 Posts: 20,966 Thanks: 2215 
2. The formula was essentially okay, but had the numerator been negative you would use its absolute value. 3. You can rotate the axes by 45°, solve the resulting (easy) problem, then reverse the rotation. That isn't the only method, of course. 
May 3rd, 2009, 02:52 AM  #13  
Newbie Joined: Mar 2009 Posts: 16 Thanks: 0  Re: Quote:
 
May 3rd, 2009, 03:43 AM  #14 
Global Moderator Joined: Dec 2006 Posts: 20,966 Thanks: 2215 
What makes you think it wouldn't be parallel to one of the axes?

May 3rd, 2009, 04:01 AM  #15 
Newbie Joined: Mar 2009 Posts: 16 Thanks: 0  Re: please help...geometry
sorry ... i made mistake in rotating axes ... 
May 3rd, 2009, 04:24 AM  #16 
Newbie Joined: Mar 2009 Posts: 16 Thanks: 0  Re: please help...geometry
ok i get something like this 

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