Math Problem Statement

a quadratic function y=a(x-b)^2+c passes through the points (-2,0) and (6,0). its maximum y value is 48. find the values of a, b, and c.

Solution

To determine the values of aa, bb, and cc for the quadratic function y=a(xb)2+cy = a(x - b)^2 + c, we analyze the given information:

Step 1: Identify the roots

The quadratic function has roots at x=2x = -2 and x=6x = 6, as it passes through (2,0)(-2, 0) and (6,0)(6, 0). The midpoint of the roots gives the xx-coordinate of the vertex: b=2+62=2.b = \frac{-2 + 6}{2} = 2. So, the vertex is at x=2x = 2, and the equation becomes: y=a(x2)2+c.y = a(x - 2)^2 + c.

Step 2: Use the maximum yy-value

The maximum value of yy is 4848, which occurs at the vertex (2,c)(2, c). Therefore: c=48.c = 48. Now the equation becomes: y=a(x2)2+48.y = a(x - 2)^2 + 48.

Step 3: Use the roots to solve for aa

The function passes through the roots (2,0)(-2, 0) and (6,0)(6, 0). Substituting (2,0)(-2, 0) into the equation: 0=a((2)2)2+48.0 = a((-2) - 2)^2 + 48. Simplify: 0=a(4)2+48.0 = a(-4)^2 + 48. 0=16a+48.0 = 16a + 48. 16a=48a=3.16a = -48 \quad \Rightarrow \quad a = -3.

Final Answer:

The quadratic function is: y=3(x2)2+48,y = -3(x - 2)^2 + 48, and the values are: a=3,b=2,c=48.a = -3, \quad b = 2, \quad c = 48.


Would you like a graph of this function or further explanation?

Related Questions:

  1. How do we verify that the vertex is a maximum and not a minimum?
  2. What are the axis of symmetry and domain of this quadratic function?
  3. How would the function change if the maximum value were different?
  4. What is the effect of changing aa on the graph of a quadratic function?
  5. How do we derive the vertex formula for a quadratic function?

Tip:

For any quadratic function, the vertex can be found using the formula x=b2ax = -\frac{b}{2a} or the midpoint of the roots, depending on the given form of the equation!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Vertex Form
Roots of a Quadratic

Formulas

y = a(x - b)^2 + c
Vertex formula: x = (x1 + x2) / 2
Substituting known points to find parameters

Theorems

Vertex theorem for quadratics
Symmetry of roots of a quadratic

Suitable Grade Level

Grades 9-11