Math Problem Statement

Consider the following function.

f(x) = −4|x|

Graph the function using transformations or the definition of absolute value, as appropriate.

Solution

To graph the function f(x)=4xf(x) = -4|x|, we can analyze it step by step using transformations and the definition of absolute value.

Step 1: Understand the Parent Function

The parent function here is x|x|, which is the absolute value function. The graph of y=xy = |x| is a "V"-shaped graph, with a vertex at (0,0)(0, 0), where:

  • For x0x \geq 0, y=xy = x
  • For x<0x < 0, y=xy = -x

Step 2: Transformation by -4

Now, apply the transformation 4x-4|x|. This transformation does two things:

  1. Negative sign (-): Reflects the graph of x|x| over the x-axis, turning the "V" shape upside down.
  2. Vertical stretch by 4: Multiplies the output (y-values) of the function by 4, making the graph steeper.

Thus, the graph of f(x)=4xf(x) = -4|x| will have the following characteristics:

  • For x0x \geq 0, f(x)=4xf(x) = -4x
  • For x<0x < 0, f(x)=4xf(x) = 4x

Step 3: Key Points on the Graph

  • The vertex of the graph remains at (0,0)(0, 0).
  • As xx increases from 0, the graph decreases linearly with a slope of -4.
  • As xx decreases from 0, the graph increases linearly with a slope of 4.

Graph Description

  • The graph is V-shaped, opening downward, with a vertex at (0,0)(0, 0).
  • For x>0x > 0, the slope is -4 (steep negative slope).
  • For x<0x < 0, the slope is 4 (steep positive slope).

If you want to visualize it, think of an inverted, narrower "V" due to the vertical stretching and the reflection.

Would you like further details or a visual representation of this graph? Here are some related questions:

  1. How does changing the coefficient from -4 to -2 affect the graph?
  2. What would happen if the function was 4x4|x| instead of 4x-4|x|?
  3. How do transformations affect absolute value functions in general?
  4. Can you describe the domain and range of this function?
  5. How do we compute the slope of the lines for each side of the graph?

Tip: To graph absolute value functions with transformations, focus on the vertex and how reflections and stretches affect the slope and orientation.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Functions
Function Transformations

Formulas

f(x) = -4|x|
y = |x|

Theorems

Properties of Absolute Value
Transformation of Functions

Suitable Grade Level

Grades 9-10