find the length of the major axis of the ellipse with equation
We must get that in standard form, which is:
if the ellipse looks like this: ,
or if the ellipse looks like this: ,
Where the length of the major axis is and the length of
the minor axis is .
All the completing of the square and factoring has already been done, so
we can start by getting a 1 on the right. To do that, we divide through
by 36:
Simplifying,
Since 9 is greater than 4 it is of the form:
so the ellipse looks like this: ,
Therefore and .
The major axis is or or
Here is the graph. The ellipse's center is at (-4,1).
Its major axis is the green line which we see is 6 units long.
Edwin