# Thread: find equation of ellipse

1. ## find equation of ellipse

center at origin, major axis on y axis, contains points (1, 2sq root 3) and (1/2, sq root 15)
HELP???????????

2. ## Re: find equation of ellipse

$\displaystyle \frac{x^2}{a^2}+\frac{y^2}{b^2}=1$

Sub in and solve..

$\displaystyle \frac{1}{a^2}+\frac{12}{b^2}=1$

$\displaystyle \frac{1/4}{a^2}+\frac{15}{b^2}=1$

3. ## Re: find equation of ellipse

Originally Posted by sluggerbroth
center at origin, major axis on y axis, contains points (1, 2sq root 3) and (1/2, sq root 15)
$\displaystyle \dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}=1$ i is the equation. Use the given points to find $\displaystyle a^2~\&~b^2$

4. ## Re: find equation of ellipse

Originally Posted by sluggerbroth
center at origin, major axis on y axis, contains points (1, 2sq root 3) and (1/2, sq root 15)
HELP???????????
$\displaystyle \frac{1^2}{a^2} + \frac{(2\sqrt{3})^2}{b^2} = 1$

$\displaystyle \frac{\left(\frac{1}{2}\right)^2}{a^2} + \frac{(\sqrt{15})^2}{b^2} = 1$

note $\displaystyle b^2 > a^2$ ...

solve for $\displaystyle a^2$ and $\displaystyle b^2$