Math Problem Statement

Show all the work for this problem. determine whether this function has an inverse function. 1.) y = 3/x-2 - 1 2.)y = x^3 -4x +6 3.) y = ln x^2

Solution

Let's analyze each function to determine whether it has an inverse. For a function to have an inverse, it must be one-to-one. This means that each value of yy is associated with exactly one value of xx. We'll use the horizontal line test and the derivative test where applicable.

1. Function: y=3x21y = \frac{3}{x - 2} - 1

Step 1: Analyze the Function

  • This function is a transformation of the basic rational function y=1xy = \frac{1}{x}.
  • The function y=3x2y = \frac{3}{x - 2} is a horizontal stretch by a factor of 3 and a horizontal shift to the right by 2 units.
  • The subtraction of 1 indicates a downward shift by 1 unit.

Step 2: Determine if the Function is One-to-One

  • To check if the function is one-to-one, let's rewrite the equation in terms of xx and solve for xx.

Starting with: y=3x21y = \frac{3}{x - 2} - 1

Add 1 to both sides: y+1=3x2y + 1 = \frac{3}{x - 2}

Now multiply both sides by (x2)(x - 2): (y+1)(x2)=3(y + 1)(x - 2) = 3

Distribute y+1y + 1: yx+y2y2=3yx + y - 2y - 2 = 3

Solve for xx: x=3+2yy+1x = \frac{3 + 2y}{y + 1}

Since we can solve for xx uniquely in terms of yy, the function is one-to-one.

Conclusion: The function y=3x21y = \frac{3}{x - 2} - 1 has an inverse function.

2. Function: y=x34x+6y = x^3 - 4x + 6

Step 1: Analyze the Function

  • The function is a cubic polynomial, which is generally continuous and smooth.

Step 2: Determine if the Function is One-to-One

  • Let's check the derivative to determine whether the function is strictly increasing or decreasing.

The derivative is: dydx=3x24\frac{dy}{dx} = 3x^2 - 4

Step 3: Analyze the Derivative

  • Set the derivative equal to zero to find the critical points: 3x24=03x^2 - 4 = 0

Solving for xx: x2=43x=±23x^2 = \frac{4}{3} \quad \Rightarrow \quad x = \pm \frac{2}{\sqrt{3}}

  • The function changes its slope at these points, which means the function is not strictly increasing or decreasing over its entire domain.

  • Since the function can have the same yy value for different xx values, it fails the horizontal line test.

Conclusion: The function y=x34x+6y = x^3 - 4x + 6 does not have an inverse function.

3. Function: y=ln(x2)y = \ln(x^2)

Step 1: Analyze the Function

  • This function involves the natural logarithm of x2x^2.
  • Let's rewrite the function: y=ln(x2)=2lnxy = \ln(x^2) = 2\ln|x|

Step 2: Determine if the Function is One-to-One

  • Since y=2lnxy = 2\ln|x|, the function is not one-to-one because lnx\ln|x| takes the same value for both positive and negative xx.

  • For example, x=2x = 2 and x=2x = -2 give the same yy value, which means it fails the horizontal line test.

Conclusion: The function y=ln(x2)y = \ln(x^2) does not have an inverse function.


Would you like further details or have any other questions about these problems?

Here are 5 related questions to explore:

  1. How does the derivative help determine if a function is one-to-one?
  2. What is the general form of the inverse of a linear function?
  3. Can a function be one-to-one on a restricted domain even if it’s not one-to-one overall?
  4. How does the horizontal line test work in determining the existence of an inverse?
  5. What are the characteristics of logarithmic functions and their inverses?

Tip: Always consider the domain of the function when determining if it is one-to-one; different domains can change whether a function has an inverse!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Functions
Inverse Functions
Horizontal Line Test
Derivative Test

Formulas

Derivative of a function

Theorems

-

Suitable Grade Level

Advanced High School