Question 800849:  A parabola has vertex (0,0) and focus on the y axis 
a) find the equation of the parabola if it passes through the point (4,12)
 
Can you please help me out, thanks so much in advance:) 
 Found 2 solutions by  stanbon, DrBeeee: Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! A parabola has vertex (0,0) and focus on the y axis 
a) find the equation of the parabola if it passes through the point (4,12)  
-------- 
Plot those points and you will see the parabola opens up. 
Form: (x-h)^2 = p(y-k) 
------ 
Using the 2 points you get: 
(4-0)^2 = p(12-0) 
------ 
16 = 12p 
------ 
p = 4/3 
======= 
Equation: x^2 = (4/3)y 
---- 
y = (3/4)x^2 
============= 
Cheers, 
Stan H. 
============= 
 Answer by DrBeeee(684)      (Show Source): 
You can  put this solution on YOUR website! Since your parabola has its turning point at the origin, (0,0), and focus on y axis the equation is 
(1)  
I include the two zeroes in the equations to indicate that the y-intercept is zero and the axis of symmetry is at x equals zero. 
Since the parabola passes through the point (4,12) we have 
(2) 12 = a*4^2 or 
(3) 12 = 16a or 
(4) a = 12/16 or 
(5) a = 3/4 
Let's check this. 
Is (12 = 3/4*4^2)? 
Is (12 = 3/4*16)? 
Is (12 = 3*4)? 
Is (12 = 12)? Yes 
Answer: The equation of the parabola that meets the conditions stated is   
  | 
 
  
 
 |   
 
 |