Math Problem Statement

Find an equation of the form y = a(x - x1)(x - x2) of the parabola shown in the figure.

Solution

The task in the image is to find the equation of the parabola shown in the figure, in the form:

y=a(xx1)(xx2)y = a(x - x_1)(x - x_2)

where (x1,0)(x_1, 0) and (x2,0)(x_2, 0) are the x-intercepts of the parabola. From the graph, it is clear that the parabola opens upwards and passes through the point (4,4)(4, -4). We can proceed with the following steps:

Step 1: Identify the x-intercepts

From the graph, it seems that the parabola touches the x-axis at x1=4x_1 = -4 and x2=4x_2 = 4. These are the roots of the parabola.

Step 2: Use the general form y=a(xx1)(xx2)y = a(x - x_1)(x - x_2)

Substitute x1=4x_1 = -4 and x2=4x_2 = 4 into the equation:

y=a(x+4)(x4)y = a(x + 4)(x - 4)

This simplifies to:

y=a(x216)y = a(x^2 - 16)

Step 3: Find the value of aa

To determine aa, use the fact that the parabola passes through the point (0,4)(0, -4). Substitute x=0x = 0 and y=4y = -4 into the equation:

4=a(0216)-4 = a(0^2 - 16) 4=16a-4 = -16a a=416=14a = \frac{-4}{-16} = \frac{1}{4}

Step 4: Write the final equation

Substitute a=14a = \frac{1}{4} into the equation:

y=14(x216)y = \frac{1}{4}(x^2 - 16)

Thus, the equation of the parabola is:

y=14x24y = \frac{1}{4}x^2 - 4

Let me know if you need further details or clarifications!

Related Questions:

  1. How do you determine the vertex of a parabola given its equation in standard form?
  2. What is the relationship between the coefficient aa and the direction in which the parabola opens?
  3. How do you find the focus of a parabola given its equation?
  4. What are the properties of the parabola when a>0a > 0 compared to when a<0a < 0?
  5. How do the x-intercepts help in constructing the factored form of a quadratic equation?

Tip:

To easily identify the shape of a parabola, remember that when a>0a > 0, the parabola opens upwards, and when a<0a < 0, it opens downwards.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Parabolas

Formulas

y = a(x - x1)(x - x2)
y = a(x^2 - b)

Theorems

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Suitable Grade Level

Grades 9-10