SOLUTION: Given the hyperbola with the equation y^2 -9x^2 =-9 find the vertices, the foci, and the equations of the asymptotes.

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Question 1193003: Given the hyperbola with the equation y^2 -9x^2 =-9
find the vertices, the foci, and the equations of the asymptotes.

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
Instead of doing your homework for you, I'll change 9 to 16
and do this one instead: 

y%5E2+-16x%5E2+=-16

You will do yours exactly like this, step by step:

The standard form of a hyperbola is either

%28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2%22%22=%22%221 for a hyperbopla like this " )( "

or  

%28y-k%29%5E2%2Fa%5E2%2B%28x-h%29%5E2%2Fb%5E2%22%22=%22%221 for a hyperbola like this "  "

Either way, we get 1 on the right side, by dividing through by -16

y%5E2%2F%28-16%29+-16x%5E2%2F%28-16%29+=%28-16%29%2F%28-16%29

Both terms on the left must have a denominator showing, so we put
1 under the second term on the left:

-y%5E2%2F16%2Bx%5E2%2F1+=1

Reverse the terms on the left, so that the "plus" term is first:

x%5E2%2F1-y%5E2%2F16=1

We finish by rewriting x as (x-0) and y as (y-0)

%28x-0%29%5E2%2F1-%28y-0%29%5E2%2F16=1

Now that we have it in standard form, we see that it is a hyperbola
that looks like this " )( ".

Comparing it to %28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%22%22=%22%221

center = (h,k) = (0,0), a2 = 1, b2 = 16, so
a = semi-transverse axis = √1 = 1 and 
b =semi-conjugate axis = √16 = 4

The defining rectangle has corners (h±a,k±b) = (0±1,0±4) or
(1,4), (-1,4), (1,-4), (-1,-4), and the asymptotes are the
extended diagonals of the defining rectangle:

    

The vertices are the ends of the transverse axis (1,0) and (-1,0),

the foci are just beyond the vertices.

To find the foci, we must find c by the Pythagorean relation for
hyperbolas:

c%5E2=a%5E2%2Bb%5E2
c%5E2=1%5E2%2B4%5E2
c%5E2=1%2B16
c%5E2=17
c=sqrt%2817%29

So the foci are %28matrix%281%2C3%2C1%2C%22%2C%22%2C+%22%22+%2B-+sqrt%2817%29%29%29

I'll draw them in:


We find the equation of the asymptote that leans to the right.
It passes through the points (0,0) and (1,4).  It has slope
m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29+=+%284-0%29%2F%281-0%29+=+4%2F1+=+4.

It has equation
y-y%5B1%5D=m%28x-x%5B1%5D%29
y-0=4%28x-0%29
y=4x

We find the equation of the asymptote that leans to the left.
It passes through the points (0,0) and (-1,4).  It has slope
 

It has equation
y-y%5B1%5D=m%28x-x%5B1%5D%29
y-0=-4%28x-0%29
y=-4x

Now do yours the same way, step-by-step.

Edwin