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newton
Junior Member

USA
4 Posts

 Posted - 10/16/2007 :  11:26:41 I am trying to simplify the following equation:((x+c)+y) + ((x-c)+y) = 2a to get: x/a + y/(a - c) = 1. I brought the second radical to the right side of the equation, squared and start simplifying:(x+c)+y = 4a-4a ((x-c)+y) + (x-c)+y(x+c)+y) - (x-c)-y = 4a - 4a((x-c)+y)(x+c) - (x-c) = 4a-4a((x-c)+y)4cx = 4a-4a((x-c)+y)cx = a-a((x-c)+y)cx - a = -a((x-c)+y)How do I proceed from here, to get what I want above?

peppers18

124 Posts

 Posted - 10/16/2007 :  12:01:58 try this website http://en.wikipedia.org/wiki/Ellipse/Proofs

Subhotosh Khan

USA
9117 Posts

 Posted - 10/16/2007 :  12:19:55 quote:Originally posted by newtonI am trying to simplify the following equation:((x+c)+y) + ((x-c)+y) = 2a to get: x/a + y/(a - c) = 1. I brought the second radical to the right side of the equation, squared and start simplifying:(x+c)+y = 4a-4a ((x-c)+y) + (x-c)+y(x+c)+y) - (x-c)-y = 4a - 4a((x-c)+y)(x+c) - (x-c) = 4a-4a((x-c)+y)4cx = 4a-4a((x-c)+y)cx = a-a((x-c)+y)cx - a = -a((x-c)+y)<---Square both sides again and simplifyHowever I get equation of hyperbola from there - check your signsHow do I proceed from here, to get what I want above? Edited by - Subhotosh Khan on 10/16/2007 12:32:53

newton
Junior Member

USA
4 Posts

 Posted - 10/16/2007 :  15:31:49 To peppers18.I checked the website.That is exactly what I was looking for.Thank you.
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