202k views
1 vote
What is the focus point of a parabola with this equation

What is the focus point of a parabola with this equation-example-1

1 Answer

0 votes

The focus point of the parabola is (2, 0), which corresponds to option D.

To find the focus point of a parabola given by the equation
\(y = (1)/(8)(x^2 - 4x - 12)\), we can rewrite the equation in the form
\(y = a(x - h)^2 + k\), where
\((h, k)\) is the vertex of the parabola.

First, expand and simplify the given equation:


\[ y = (1)/(8)(x^2 - 4x - 12) \]


\[ y = (1)/(8)x^2 - (1)/(2)x - (3)/(2) \]

Now, factor out the leading coefficient from the
\(x^2\) and
\(x\) terms:


\[ y = (1)/(8)(x^2 - 4x) - (3)/(2) \]

Complete the square inside the parentheses. To complete the square for
\(x^2 - 4x\), add
\(\left((4)/(2)\right)^2 = 4\) inside the parentheses:


\[ y = (1)/(8)(x^2 - 4x + 4 - 4) - (3)/(2) \]


\[ y = (1)/(8)(x^2 - 4x + 4) - (1)/(2) - (3)/(2) \]


\[ y = (1)/(8)(x - 2)^2 - 2 \]

Now, the equation is in the form
\(y = a(x - h)^2 + k\) with
\((h, k) = (2, -2)\).

The focus point
\((h, k + (1)/(4a))\) for a parabola in this form is
\((2, -2 + (1)/(4 * (1)/(8)))\).


\[ k + (1)/(4a) = -2 + (1)/(4 * (1)/(8)) = -2 + 2 = 0 \]

So, the focus point is
\((2, 0)\).

Therefore, the correct answer is
\((2, 0)\).

So, the focus point of the parabola is (2, 0), which corresponds to option D.

What is the focus point of a parabola with this equation-example-1
User Malletjo
by
7.5k points