I am having trouble understanding how to find the equation of a parabola. I have the vertex and the focus. The vertex is (-2,5) and the focus is (-2,6). Can you explain in an easy to understand way how to do this kind of problem?

Respuesta :

Given:

The vertex is (-2,5).

[tex](h,k)=(-2,5)[/tex]

And the focus is (-2,6).

Required:

To find the equation of the parabola.

Explanation:

The equation of a parabola in vertex form is

[tex]y=a(x-h)^2+k[/tex]

Here,

[tex](h,k)=(-2,5)[/tex]

Therefore,

[tex]\begin{gathered} y=a(x-(-2))^2+5 \\ \\ y=a(x+2)^2+5 \end{gathered}[/tex]

And given that focus is

[tex](h,k+\frac{1}{4}a)=(-2,6)[/tex][tex]\begin{gathered} k+\frac{1}{4}a=6 \\ \\ 5+\frac{1}{4}a=6 \\ \\ \frac{1}{4}a=6-5 \\ \\ \frac{1}{4}a=1 \\ \\ a=4 \end{gathered}[/tex]

Therefore, the equation of parabola is,

[tex]y=4(x+2)^2+5[/tex]

Final Answer:

The equation of parabola is,

[tex]y=4(x+2)^{2}+5[/tex]