# How do you write the equation of the hyperbola given Foci: (0,-9),(0,9) and vertices (0,-3sqrt5), (0,3sqrt5)?

##### 1 Answer

Because it is the y coordinate that is changing for the given points, use the vertical transverse axis form:

vertices:

foci:

#### Explanation:

Using the given points, write the following equations:

To obtain the value of k, add equations [3] and [4]:

To obtain the value of a, substitute 0 for k into equation [4]:

Substitute the known values of "k" and "a" into equation 6 and solve for b:

Substitute the known values into equation [1]:

Here is a graph of equation [7] with vertices and foci: