Question 3 of 10

Which equation describes a parabola that opens left or right and whose vertex is at the point [tex](h, v)[/tex]?

A. [tex]y = a(x - v)^2 + h[/tex]
B. [tex]x = a(v - h)^2 + v[/tex]
C. [tex]y = a(x - h)^2 + v[/tex]
D. [tex]x = a(y - v)^2 + h[/tex]



Answer :

To determine which equation describes a parabola that opens left or right with its vertex at the point [tex]\((h, v)\)[/tex], we need to understand the general forms of parabolic equations.

1. Parabolas that open up or down:
The standard form for a parabola that opens up or down is:
[tex]\[ y = a(x - h)^2 + v \][/tex]
Here, [tex]\((h, v)\)[/tex] is the vertex of the parabola.

2. Parabolas that open left or right:
The standard form for a parabola that opens left or right is:
[tex]\[ x = a(y - v)^2 + h \][/tex]
Again, [tex]\((h, v)\)[/tex] is the vertex of the parabola.

Now, let's analyze the given options:

- Option A: [tex]\( y = a(x - v)^2 + h \)[/tex]

This describes a parabola that opens up or down, with its vertex at [tex]\((v, h)\)[/tex]. This equation does not fulfill the requirement of opening left or right. Therefore, it’s incorrect.

- Option B: [tex]\( x = a(v - h)^2 + v \)[/tex]

This form doesn’t correspond to any standard form of parabolic equations. Therefore, this option can be discarded as incorrect.

- Option C: [tex]\( y = a(x - h)^2 + v \)[/tex]

This also describes a parabola that opens up or down, with its vertex at [tex]\((h, v)\)[/tex]. This is not what we need since we are looking for a parabola that opens to the left or right.

- Option D: [tex]\( x = a(y - v)^2 + h \)[/tex]

This describes a parabola that opens to the left or right, with its vertex at [tex]\((h, v)\)[/tex]. This matches the requirement perfectly.

Thus, the correct answer is:
[tex]\[ \boxed{D} \][/tex]