Questions: Find the coordinates of the vertex and the focus for the parabola given by the following equation:
x^2-2x-8y-63=0
Round all answers to 2 places after the decimal point, if necessary.
Coordinates of the vertex: ( , )
Coordinates of the focus: , )
Transcript text: Find the coordinates of the vertex and the focus for the parabola given by the following equation:
\[
x^{2}-2 x-8 y-63=0
\]
Round all answers to 2 places after the decimal point, if necessary.
Coordinates of the vertex: ( $\square$ , $\square$ )
Coordinates of the focus: $\square$ , $\square$ )
Solution
Solution Steps
Step 1: Rewrite the equation in standard form
Start by rewriting the given equation:
\[
x^{2} - 2x - 8y - 63 = 0
\]
Move the \( y \)-terms and constants to the other side:
\[
x^{2} - 2x = 8y + 63
\]
Step 2: Complete the square for the \( x \)-terms
To complete the square for \( x^{2} - 2x \), take half of the coefficient of \( x \), square it, and add it to both sides:
\[
x^{2} - 2x + 1 = 8y + 63 + 1
\]
This simplifies to:
\[
(x - 1)^{2} = 8y + 64
\]
Step 3: Rewrite in vertex form
Divide both sides by 8 to isolate \( y \):
\[
\frac{(x - 1)^{2}}{8} = y + 8
\]
Rearrange to write in vertex form:
\[
y = \frac{1}{8}(x - 1)^{2} - 8
\]
From this, the vertex is at \( (1, -8) \).
Step 4: Identify the focus
The standard form of a parabola is \( y = \frac{1}{4p}(x - h)^{2} + k \), where \( (h, k) \) is the vertex and \( p \) is the distance from the vertex to the focus. Comparing:
\[
\frac{1}{4p} = \frac{1}{8} \implies p = 2
\]
Since the parabola opens upwards, the focus is at \( (1, -8 + 2) = (1, -6) \).