Math Problem Statement

Describe the process to find the inverse of a function.

Solution

Finding the inverse of a function involves a step-by-step process to reverse the roles of inputs and outputs. Here's a detailed description of the process:

Step-by-Step Process to Find the Inverse of a Function

  1. Write the function as y=f(x)y = f(x): Begin by expressing the given function in the form y=f(x)y = f(x). This step makes it easier to work with the function algebraically.

  2. Interchange xx and yy: To find the inverse, swap the roles of xx and yy. This reflects the idea that for an inverse, the output becomes the input, and the input becomes the output. So the new equation will be x=f(y)x = f(y).

  3. Solve for yy: Solve the new equation for yy. The resulting expression for yy will represent the inverse function f1(x)f^{-1}(x).

  4. Express the inverse function: After solving for yy, replace yy with f1(x)f^{-1}(x). This final expression is the inverse of the original function.

  5. Verify the result (optional): To check if your inverse function is correct, you can verify by confirming that f(f1(x))=xf(f^{-1}(x)) = x and f1(f(x))=xf^{-1}(f(x)) = x.

Example:

Let's consider a function f(x)=2x+3f(x) = 2x + 3.

  1. Write it as y=2x+3y = 2x + 3.
  2. Swap xx and yy: x=2y+3x = 2y + 3.
  3. Solve for yy: x3=2yy=x32x - 3 = 2y \quad \Rightarrow \quad y = \frac{x - 3}{2}
  4. Therefore, the inverse function is f1(x)=x32f^{-1}(x) = \frac{x - 3}{2}.
  5. Verify by checking: f(f1(x))=2(x32)+3=xf(f^{-1}(x)) = 2\left(\frac{x - 3}{2}\right) + 3 = x f1(f(x))=2x+332=xf^{-1}(f(x)) = \frac{2x + 3 - 3}{2} = x

This confirms that the inverse is correct.

Would you like more details or have any questions?


Related Questions:

  1. What are the conditions for a function to have an inverse?
  2. How do you find the inverse of a quadratic function?
  3. What happens if a function is not one-to-one? Can it still have an inverse?
  4. How can you graphically verify the inverse of a function?
  5. What is the relationship between a function and its inverse?

Tip: A function must be one-to-one (injective) to have an inverse, which means it passes the horizontal line test (each output corresponds to exactly one input).

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Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Inverse Functions

Formulas

Inverse Function: f^{-1}(x)
Function Composition: f(f^{-1}(x)) = x and f^{-1}(f(x)) = x

Theorems

Horizontal Line Test (One-to-One Function)
Inverse Function Theorem

Suitable Grade Level

Grades 9-12