Sunday

April 20, 2014

April 20, 2014

Posted by **Tim** on Wednesday, April 30, 2008 at 8:40pm.

I need to find the equation of a parabola. I am not sure if this is the correct way or if I have the correct answer.

Vertex at origin, focus is at (0,3)

Equation of parabola

vertex (0,0) focus (0,3)

focus (h,k+p)

(0,0+3)

y=0-3

directrix y=-3

a=(1/4)(p)

a=(1/4(-3))=(-1/12)

a=(-1/12) h=0 k=0

y=(-1/12)(x-0)^2+0

my answer is: y=(-1/12)(x^2)+0

- Algebra -
**Reiny**, Wednesday, April 30, 2008 at 9:09pmshouldn't your parabola open upwards ?

your -1/12x^2.... makes it open down.

I do it this way:

let P(x,y) be any point on the parabola

by definition, the distance from P to the focal point is equal to the distance to the directrix --->

√(x^2 + (y-3)^2) = √(y+3)^2)

square both sides, and simplify to get

y = (1/12)x^2

**Related Questions**

algebra problem - I need to find the equation of a parabola. I am not sure if ...

college algebra--need help please!! - solve the following exponential equation. ...

Algebra II - In this set of eight problems, we have to match each equation with ...

algebra - 6. Find the equation of each parabola described below. a) parabola ...

Algebra - I'm trying this again, I'd like the quadratic form, so i can then work...

Calculus - Great! I understand now that C0=f(a) c1=f'(a) c2=f"(a)/2 Now, If I am...

Algebra: Parabolas - I have a math problem that requires me to find the focal ...

Algebra - Could someone correct my answers and help with the other problems? 1. ...

Albebra - Find the vertex of the function y = –x2 + 2x + 8. It is where the ...

Algebra - Hi, Any help on this would be very much appreciated. The graph y=3x^2+...