# Ellipse formula

• May 8th 2011, 11:12 AM
homeylova223
Ellipse formula
For the equation of each ellipse find the coordinates of the centre,foci, and vertices.

1. 49x^2+16y^2+160y-384=0
(49x^2+0+0)+ 16(y^2+10y+25)= 384+16(25) This is what I did
(0x+0)+16(y+5)^2=784

0x/784+(y+5)^2/49 Have I set up the equation right?(Giggle)
• May 8th 2011, 11:38 AM
topsquark
Quote:

Originally Posted by homeylova223
For the equation of each ellipse find the coordinates of the centre,foci, and vertices.

1. 49x^2+16y^2+160y-384=0
(49x^2+0+0)+ 16(y^2+10y+25)= 384+16(25) This is what I did
(0x+0)+16(y+5)^2=784

Where did the 49x^2 go??

-Dan
• May 8th 2011, 02:35 PM
homeylova223
With 49x^2 I am not sure how to complete the square so I did (0/98)^2=0.
• May 8th 2011, 04:23 PM
HallsofIvy
Yes, so it is 49(x^2- 0)= 49x^2- it already is a perfect square.
$49x^2+ 16(y+5)^2= 784$

Now divide both sides by 49(16)