Math Problem Statement

ACTIVITY #4 PARABOLA

This activity will be our last official activity for the 1 quarter. This will be answered on a piece of graphing paper. This can be answered by solo or with a chosen pair/trio and don't forget to write your name/the names of your partner. This activity will have a total of 20 points. Goodluck!

On the given parabola equations, find the following:

a) Vertex

b) Focus

c) Endpoints of Latus Rectum

d) Directrix

e) Axis of Symmetry

g) Graph

  1. x²-2x+1=8y-16

Solution

Let's work through the given parabola equation step-by-step:

Given Equation:

x22x+1=8y16x^2 - 2x + 1 = 8y - 16

We'll first rewrite it in a more recognizable form for a parabola, and then extract all the necessary properties.

Step 1: Simplify and complete the square

Start by simplifying both sides to make it easier to analyze.

x22x+1=8y16x^2 - 2x + 1 = 8y - 16

We can subtract 11 from both sides:

x22x=8y17x^2 - 2x = 8y - 17

Next, complete the square on the left-hand side:

x22x=(x1)2x^2 - 2x = (x - 1)^2

So, the equation becomes:

(x1)2=8y17(x - 1)^2 = 8y - 17

Add 17 to both sides:

(x1)2=8(y2.125)(x - 1)^2 = 8(y - 2.125)

Now we have the equation in the standard form of a parabola: (xh)2=4p(yk)(x - h)^2 = 4p(y - k) Where (h,k)(h, k) is the vertex and pp is the distance from the vertex to the focus (and to the directrix).

Step 2: Identify the Vertex

By comparing the equation (x1)2=8(y2.125)(x - 1)^2 = 8(y - 2.125) with the standard form, we can see that the vertex is:

Vertex: (1,2.125)(1, 2.125)

Step 3: Identify the Focus

We know that 4p=84p = 8, so: p=84=2p = \frac{8}{4} = 2

Since this is a parabola that opens vertically (upward), the focus is 2 units above the vertex.

Focus: (1,2.125+2)=(1,4.125)(1, 2.125 + 2) = (1, 4.125)

Step 4: Find the Directrix

The directrix is a horizontal line pp units below the vertex. So, we subtract 22 from the yy-coordinate of the vertex.

Directrix: y=2.1252=0.125y = 2.125 - 2 = 0.125

Step 5: Axis of Symmetry

The axis of symmetry is the vertical line that passes through the vertex. For this equation, it is:

Axis of Symmetry: x=1x = 1

Step 6: Endpoints of the Latus Rectum

The latus rectum is a line segment perpendicular to the axis of symmetry and passes through the focus. The length of the latus rectum is 4p=84p = 8, and since the parabola opens vertically, the endpoints are 4 units horizontally from the focus.

Thus, the endpoints are:

Endpoints of the Latus Rectum: (14,4.125)=(3,4.125)\left(1 - 4, 4.125\right) = (-3, 4.125) (1+4,4.125)=(5,4.125)\left(1 + 4, 4.125\right) = (5, 4.125)

Step 7: Graph

To graph this parabola:

  • Plot the vertex at (1,2.125)(1, 2.125).
  • Plot the focus at (1,4.125)(1, 4.125).
  • Draw the directrix as the horizontal line y=0.125y = 0.125.
  • Draw the axis of symmetry along x=1x = 1.
  • Mark the endpoints of the latus rectum at (3,4.125)(-3, 4.125) and (5,4.125)(5, 4.125).
  • Sketch the parabola passing through these points, opening upwards.

Would you like a visual graph representation or any other further details?

Here are some related questions:

  1. How do we determine the direction in which a parabola opens?
  2. What happens to the shape of the parabola if pp is increased or decreased?
  3. What is the geometric significance of the latus rectum in parabolas?
  4. Can a parabola open horizontally, and how would the equation look in that case?
  5. What is the relationship between the vertex, focus, and directrix of a parabola?

Tip: When completing the square, always ensure that you balance both sides of the equation, especially when working with a constant.

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Math Problem Analysis

Mathematical Concepts

Parabolas
Conic Sections
Vertex Form of a Parabola
Graphing Parabolas

Formulas

(x - h)^2 = 4p(y - k)
Formula for vertex of a parabola
Formula for focus of a parabola
Formula for directrix of a parabola
Formula for endpoints of the latus rectum

Theorems

Properties of parabolas
Relationship between focus, vertex, and directrix

Suitable Grade Level

Grades 10-12