Math Problem Statement

Find the inverse function of the following functions: 1) f(x) = 3x + 1, 2) f(x) = x^3 - 2, 3) f(x) = 2x + 1, 4) f(x) = x^2 + 4, 5) f(x) = 2x + 6.

Solution

The task is to find the inverse function of the given functions in the image. Let me solve each of the problems step by step.

Steps to find the inverse function:

  1. Replace f(x)f(x) with yy.
  2. Solve for xx in terms of yy.
  3. Switch xx and yy to get the inverse function, f1(x)f^{-1}(x).

1) f(x)=3x+1f(x) = 3x + 1

Step 1: Replace f(x)f(x) with yy: y=3x+1y = 3x + 1

Step 2: Solve for xx: y1=3xx=y13y - 1 = 3x \quad \Rightarrow \quad x = \frac{y - 1}{3}

Step 3: Switch xx and yy: f1(x)=x13f^{-1}(x) = \frac{x - 1}{3}


2) f(x)=x32f(x) = x^3 - 2

Step 1: Replace f(x)f(x) with yy: y=x32y = x^3 - 2

Step 2: Solve for xx: y+2=x3x=y+23y + 2 = x^3 \quad \Rightarrow \quad x = \sqrt[3]{y + 2}

Step 3: Switch xx and yy: f1(x)=x+23f^{-1}(x) = \sqrt[3]{x + 2}


3) f(x)=2x+1f(x) = 2x + 1

Step 1: Replace f(x)f(x) with yy: y=2x+1y = 2x + 1

Step 2: Solve for xx: y1=2xx=y12y - 1 = 2x \quad \Rightarrow \quad x = \frac{y - 1}{2}

Step 3: Switch xx and yy: f1(x)=x12f^{-1}(x) = \frac{x - 1}{2}


4) f(x)=x2+4f(x) = x^2 + 4

Note: Since this is a quadratic, it has no inverse unless we restrict the domain. I'll proceed assuming the domain is restricted (i.e., x0x \geq 0).

Step 1: Replace f(x)f(x) with yy: y=x2+4y = x^2 + 4

Step 2: Solve for xx: y4=x2x=y4y - 4 = x^2 \quad \Rightarrow \quad x = \sqrt{y - 4}

Step 3: Switch xx and yy: f1(x)=x4f^{-1}(x) = \sqrt{x - 4}


5) f(x)=2x+6f(x) = 2x + 6

Step 1: Replace f(x)f(x) with yy: y=2x+6y = 2x + 6

Step 2: Solve for xx: y6=2xx=y62y - 6 = 2x \quad \Rightarrow \quad x = \frac{y - 6}{2}

Step 3: Switch xx and yy: f1(x)=x62f^{-1}(x) = \frac{x - 6}{2}


Would you like further explanation or details on any of these steps?

Related Questions:

  1. What is the general method to determine if a function has an inverse?
  2. Can all quadratic functions have inverses? Why or why not?
  3. How can domain restrictions affect the existence of an inverse function?
  4. What is the significance of switching xx and yy in the process of finding the inverse?
  5. How do transformations like shifts and stretches affect the inverse of a function?

Tip:

Always check if the function is one-to-one before finding its inverse. Functions that aren't one-to-one will need domain restrictions to have an inverse.

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Math Problem Analysis

Mathematical Concepts

Algebra
Inverse Functions

Formulas

Inverse function formula: f^{-1}(x) is the function that satisfies f(f^{-1}(x)) = x
Solving for x in terms of y: Switch variables to find the inverse.

Theorems

To find an inverse, a function must be one-to-one (injective).
Quadratic functions like x^2 + 4 may require domain restrictions for an inverse.

Suitable Grade Level

Grades 10-12