Math Problem Statement

  1. (A) Transform the general equation into standard form, if the given equation of a parabola is y² + 4x 14y= -53.

(B) From the equation given above at number 1 (A), give the following

coordinates:

a. Vertex

b. Focus

c. Directrix

d. Axis of symmetry

Solution

1 (A). Transforming the general equation of the parabola into standard form:

The given equation is: y2+4x14y=53y^2 + 4x - 14y = -53

We will first rearrange the terms and complete the square to convert this into the standard form of a parabola.

  1. Rearrange the terms by isolating xx: y214y=4x53y^2 - 14y = -4x - 53

  2. Complete the square on the left side for the yy-terms. To complete the square, take half of the coefficient of yy (which is 14-14), square it, and add it to both sides. Half of 14-14 is 7-7, and (7)2=49(-7)^2 = 49.

    So, we add 49 to both sides: y214y+49=4x53+49y^2 - 14y + 49 = -4x - 53 + 49 Simplifying: (y7)2=4x4(y - 7)^2 = -4x - 4 (y7)2=4(x+1)(y - 7)^2 = -4(x + 1)

Thus, the equation in standard form is: (y7)2=4(x+1)(y - 7)^2 = -4(x + 1)

This is the standard form of a parabola that opens left or right, (yk)2=4p(xh)(y - k)^2 = 4p(x - h), where (h,k)(h, k) is the vertex and pp determines the direction and distance of the focus from the vertex.

1 (B). Finding the coordinates:

From the equation (y7)2=4(x+1)(y - 7)^2 = -4(x + 1), we can extract the following details:

  1. Vertex: The vertex (h,k)(h, k) is given by the point (1,7)(-1, 7), directly from the form of the equation.

    Vertex: (1,7)(-1, 7)

  2. Focus: The general equation is (yk)2=4p(xh)(y - k)^2 = 4p(x - h). In our equation, 4p=44p = -4, so p=1p = -1. Since the parabola opens to the left (because pp is negative), the focus is located 1 unit to the left of the vertex. Thus, the focus is at:

    Focus: (2,7)(-2, 7)

  3. Directrix: The directrix is a vertical line, located pp units to the right of the vertex. Since p=1p = -1, the directrix is 1 unit to the right of the vertex, at:

    Directrix: x=0x = 0

  4. Axis of Symmetry: The axis of symmetry is the horizontal line passing through the vertex, parallel to the yy-axis. The equation of this line is:

    Axis of Symmetry: y=7y = 7


Would you like further clarification on any of these steps?

5 Related Questions:

  1. How do you complete the square for quadratic terms?
  2. What does the value of pp represent in the standard form of a parabola?
  3. How does the equation change if the parabola opens upwards or downwards?
  4. What is the general form of the equation for a parabola that opens vertically?
  5. How do you derive the equation of the directrix from the standard form of a parabola?

Tip:

Always remember that in the standard form of a parabola (yk)2=4p(xh)(y - k)^2 = 4p(x - h), the sign of pp tells you the direction in which the parabola opens.

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Math Problem Analysis

Mathematical Concepts

Parabola
Completing the Square
Coordinate Geometry

Formulas

Standard form of a parabola: (y - k)^2 = 4p(x - h)
Completing the square for quadratic equations

Theorems

Properties of Parabolas
Equation of a Parabola in Standard Form

Suitable Grade Level

Grades 9-11