# Finding the equation of a hyperbola

1. Dec 19, 2009

### farmd684

1. The problem statement, all variables and given/known data

Problem : Find an equation and sketch in x-y coordinates for the Hyperbola with vertex (-1,7) and asymptotes y-5=+- (x+1)

3. The attempt at a solution

To find the equation of the hyperbola i have to find the length of a ( distance from center to vertex in focal axis ) and b to put them in the equation y^2/a^2 - x^2/b^2 = 1 so far i have found the center (-1,5) and vertex are (-1,7) and (-1,3) so i get a = 2 But how can i get the value of b to put it in the equation ? Thanks :)

2. Dec 19, 2009

### tiny-tim

Hi farmd684!

(try using the X2 tag just above the Reply box )

If the question gives you lemons … make lemonade!

For y2/a2 - x2/b2 = 1, what is the slope of the asymptotes?

3. Dec 19, 2009

### farmd684

the slope i guess is a/b for y2/x2. Then what should i do.

4. Dec 19, 2009

### tiny-tim

Well, if you know a/b and you know a, then b = … ?

5. Dec 19, 2009

Thanks