Math Problem Statement

The quadratic function g(x) = -2x^2 + 4x + 30 can be obtained by the function f(x) = x^2 by a sequence of transformations. (a) Describe those transformations in the right order. (b) The point A(2, 4) lies on y = f(x). Find the corresponding point on y = g(x).

Solution

Let's analyze the problem step by step.

Problem Overview

The given problem involves the quadratic function f(x)=x2f(x) = x^2 and how it is transformed into g(x)=2x2+4x+30g(x) = -2x^2 + 4x + 30. The task includes:

(a) Describing the transformations applied to f(x)=x2f(x) = x^2 in the correct order.
(b) Finding the point on g(x)g(x) that corresponds to the given point A(2,4)A(2, 4) on y=f(x)y = f(x).


Part (a): Sequence of Transformations

To transform f(x)=x2f(x) = x^2 into g(x)=2x2+4x+30g(x) = -2x^2 + 4x + 30, we analyze the function step by step:

  1. Start with f(x)=x2f(x) = x^2:

    • Begin with the base quadratic.
  2. Introduce the coefficient of 2-2:

    • Scaling by 2-2 reflects f(x)f(x) across the xx-axis and stretches it vertically by a factor of 2. The function becomes 2x2-2x^2.
  3. Add 4x4x:

    • Adding 4x4x represents a horizontal shift and tilts the parabola. The function now becomes 2x2+4x-2x^2 + 4x.
  4. Add 3030:

    • Finally, adding 3030 shifts the function vertically upwards by 30 units, giving the final form g(x)=2x2+4x+30g(x) = -2x^2 + 4x + 30.

Final Transformations (in order):

  1. Reflect over the xx-axis and stretch by a factor of 2.
  2. Add 4x4x, introducing a horizontal shift.
  3. Shift the function up by 30.

Part (b): Corresponding Point

The given point A(2,4)A(2, 4) lies on y=f(x)=x2y = f(x) = x^2. To find the corresponding point on y=g(x)y = g(x), follow these steps:

  1. Start with A(2,4)A(2, 4).

    • Since the transformations affect the function, we substitute x=2x = 2 into g(x)g(x) to calculate the corresponding yy-value.
  2. Substitute x=2x = 2 into g(x)=2x2+4x+30g(x) = -2x^2 + 4x + 30:
    g(2)=2(22)+4(2)+30g(2) = -2(2^2) + 4(2) + 30 g(2)=2(4)+8+30=8+8+30=30g(2) = -2(4) + 8 + 30 = -8 + 8 + 30 = 30

  3. The corresponding point is B(2,30)B(2, 30).


Final Answers:

(a) The transformations are:

  1. Reflect f(x)f(x) over the xx-axis and stretch by a factor of 2.
  2. Add 4x4x to shift horizontally.
  3. Shift up by 30.

(b) The corresponding point is B(2,30)B(2, 30).


Would you like a deeper explanation of any step or further assistance?

Here are five related questions to explore:

  1. How do horizontal shifts impact quadratic functions?
  2. What is the geometric meaning of adding 4x4x to a quadratic equation?
  3. How would the transformation change if g(x)g(x) included 4x-4x instead?
  4. How can we derive the vertex of g(x)=2x2+4x+30g(x) = -2x^2 + 4x + 30?
  5. What is the impact of a reflection over the xx-axis on a function's graph?

Tip: When working with transformations, always apply them sequentially to understand their cumulative effects!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Transformations of Functions

Formulas

g(x) = -2x^2 + 4x + 30
f(x) = x^2

Theorems

Transformation Rules for Quadratic Functions

Suitable Grade Level

Grades 9-12