Question

Find the length of the major axis for this ellipse:
x^2+4y^2=33
Length of major axis=

__square root of _____

Answer 1

An ellipse is of the form
\[\frac {x^2} {a^2} + \frac {y^2}{ b^2}=1\]
2a is the length of the major axis
2b is the length of the minor axis
Can you do it now ?

Answer 2

I know that, but they are asking it in a radical form, as is _____square root of ______ There is where I got lost...

Answer 3

Can you convert the equation into the form of ellipse equation?

Answer 4

yes, but what do I do with the 4y^2/33?

Answer 5

We need 2a, don't bother about b^2!!

Answer 6

The major axis is parallel to the x-axis.

Answer 7

you could write in the form as
\[\frac {x^2}{33}+\frac {y^2} {\frac {33}{4}}=1\]
\[\large \frac {x^2}{\sqrt {33}}+\frac {y^2} {\sqrt{\frac {33}{4}}}=1\]
\[\large \frac {x^2}{\sqrt {33}}+\frac {y^2} {{\frac {\sqrt{33}}{2}}}=1\]

Answer 8

use the number under x^2. Since it is larger than the other one, it is a measure of the major axis. \[a=\sqrt{33}\]

Answer 9

thank you guys :) I got it :D