# Thread: Parabola, ellipses, or hyperbolas help!

1. ## Parabola, ellipses, or hyperbolas help!

Need help with a problem.

X^2 + (y+1)^2/3 =1.
It is x squared plus y+1 squared divided by 3 =1.

2. ## Re: Parabola, ellipses, or hyperbolas help!

I believe it's an ellipse.

3. ## Re: Parabola, ellipses, or hyperbolas help!

Originally Posted by Nfalconer
Need help with a problem.
X^2 + (y+1)^2/3 =1.
It is x squared plus y+1 squared divided by 3 =1.

Is it $x^2+\dfrac{(y+1)^2}{3}=1$ or $\large{x^2+(y+1)^{\frac{2}{3}}=1?}$

4. ## Re: Parabola, ellipses, or hyperbolas help!

It is the first one. I am trying to figure out foci and vertices. I know it is a vertical ellipse but that's it. Need to find a b and c.

5. ## Re: Parabola, ellipses, or hyperbolas help!

Originally Posted by Nfalconer
It is the first one. I am trying to figure out foci and vertices. I know it is a vertical ellipse but that's it. Need to find a b and c.
Do you see how you could have avoided that confusion?

Write as $x^2+\frac{(y+1)^2}{3}=1$.

The center of the ellipse is $(0,-1)$.

The foci are equally distance on each side of the center on the major axis.
What is the major axis?

6. ## Re: Parabola, ellipses, or hyperbolas help!

I got foci 1 as (0,.4) and foci 2 as ( 0, -2.4)

7. ## Re: Parabola, ellipses, or hyperbolas help!

For the vertices I got (0,.7) and (0,-2.7)?

8. ## Re: Parabola, ellipses, or hyperbolas help!

Originally Posted by Nfalconer
I got foci 1 as (0,.4) and foci 2 as ( 0, -2.4)
How did you get those values?

9. ## Re: Parabola, ellipses, or hyperbolas help!

For foci 1 I did (h,k+c) so 0, -1+1.4=(0,.4) and foci 2 I did (h, k-c)= (0, -1-1.4)= (0,-2.4). Is that wrong?

10. ## Re: Parabola, ellipses, or hyperbolas help!

And the vertices I did (0, -1+1.7) and (0,-1.7+-2)

11. ## Re: Parabola, ellipses, or hyperbolas help!

Originally Posted by Nfalconer
And the vertices I did (0, -1+1.7) and (0,-1.7+-2)
Tell us how you got $c$. Be detailed, please.

12. ## Re: Parabola, ellipses, or hyperbolas help!

I got c by doing 3-1=2 then got +or- 1.4

13. ## Re: Parabola, ellipses, or hyperbolas help!

I did A(3) - B(1) to get 2

14. ## Re: Parabola, ellipses, or hyperbolas help!

I messed up everything didn't I?

15. ## Re: Parabola, ellipses, or hyperbolas help!

Originally Posted by Nfalconer
And the vertices I did (0, -1+1.7) and (0,-1.7+-2)
I'm going to slip this in here: It is better to give exact values rather than use decimals. ie. $\displaystyle ( 0, ~ -1 + \sqrt{3} ); ( 0, -1 - \sqrt{3} )$

-Dan

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