Thread: Ellipse Question
View Single Post
  #2  
Old October 19th, 2009, 01:24 PM
earboth's Avatar
earboth earboth is offline
Super Member

  
Join Date: Jan 2006
Location: Germany
Posts: 4,584
Country:
Thanks: 190
Thanked 2,012 Times in 1,843 Posts
earboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond reputeearboth has a reputation beyond repute
Default
Quote:
Originally Posted by Kevlar View Post
Find the co-ordinates of the centre and foci of the ellipse with equation
25x^2+16y^2-100x-256y+724=0
What are the coordinated of its verices and the eqns of the directrices?

I've managed to manipulate the eqn to this form

\frac{(x-2)^2}{16}+\frac{(y-8)^2}{25}=1

Therefore got the centre as (2,8).

I did vertex, directrix and foci for parabolas but not for an ellipse what are the formula? :s i've tried looking them up on the web but it's all confusing. So far i think

Directrix=+-\frac{a^2}{c}

Can someone help me out with just this one ? >.< got a whole load more of em to work through that are similar just im stuck at the first hurdle haha
Have a look here: Ellipse -- from Wolfram MathWorld

(You have to scroll down a little bit!)
Reply With Quote