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Jonask
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prove that the directrix of an ellipse is \[x=\frac{a^2}{c}\]
 one year ago
 one year ago
Jonask Group Title
prove that the directrix of an ellipse is \[x=\frac{a^2}{c}\]
 one year ago
 one year ago

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Jonask Group TitleBest ResponseYou've already chosen the best response.0
this ellipse is the general ellipse with \[\frac{ x^2 }{ a^2}+\frac{ y^2 }{ b^2 }=1,a>b\]
 one year ago

Jonask Group TitleBest ResponseYou've already chosen the best response.0
i have the proof but i dont understand the ratio set up here can i post the link
 one year ago

Jonask Group TitleBest ResponseYou've already chosen the best response.0
http://mathworld.wolfram.com/Ellipse.html
 one year ago

Jonask Group TitleBest ResponseYou've already chosen the best response.0
\[r=\frac{ ac }{ da }=\frac{ a }{ d }\]
 one year ago

Jonask Group TitleBest ResponseYou've already chosen the best response.0
\[a^2=b^2+c^2 i dont get this ratio .why it holds
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
??dw:1364055606757:dwdw:1364055629069:dw
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
i haven't done conics for quite while, but this shouldn't be difficult.dw:1364055735803:dw
 one year ago

Jonask Group TitleBest ResponseYou've already chosen the best response.0
i mean http://mathworld.wolfram.com/images/equations/Ellipse/NumberedEquation12.gif
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
what's r there?
 one year ago

Jonask Group TitleBest ResponseYou've already chosen the best response.0
its defined in the 1st link
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
can't find it ... equation no?
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
what is this 'c' again?
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
this 'c' looks like foci.
 one year ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
this is pretty ovbioius ... this ratio must be constant
 one year ago
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