Math Problem Statement

For the function f(x) = 3x + 5, find the domain, range, and inverse along with their respective domain and range.

Solution

Let's work through the problem in the image for f(x)=3x+5f(x) = 3x + 5.

(a) Domain of ff:

The function f(x)=3x+5f(x) = 3x + 5 is a linear function, which means it is defined for all real values of xx. Therefore, the domain of ff is: Domain of f=(,)\text{Domain of } f = (-\infty, \infty)

(b) Range of ff:

Since f(x)=3x+5f(x) = 3x + 5 is a linear function with no restrictions, the range is also all real numbers. As xx takes on any real value, f(x)f(x) covers all real numbers. Hence, the range of ff is: Range of f=(,)\text{Range of } f = (-\infty, \infty)

(c) Formula for f1f^{-1} (Inverse of ff):

To find the inverse, we follow these steps:

  1. Start with the equation: y=3x+5y = 3x + 5.
  2. Solve for xx: y5=3xy - 5 = 3x x=y53x = \frac{y - 5}{3}
  3. Replace yy with xx to get the inverse function: f1(x)=x53f^{-1}(x) = \frac{x - 5}{3}

(d) Domain of f1f^{-1}:

Since the domain of the inverse function is the range of the original function, and we found that the range of f(x)f(x) is all real numbers, the domain of f1(x)f^{-1}(x) is: Domain of f1=(,)\text{Domain of } f^{-1} = (-\infty, \infty)

(e) Range of f1f^{-1}:

The range of f1f^{-1} is the same as the domain of the original function f(x)f(x), which is also all real numbers. Hence, the range of f1(x)f^{-1}(x) is: Range of f1=(,)\text{Range of } f^{-1} = (-\infty, \infty)


Would you like further explanation on any of these parts? Let me know if you have any questions!

Here are 5 related questions for further practice:

  1. What is the inverse of the function f(x)=2x3f(x) = 2x - 3?
  2. How do you find the inverse of a quadratic function?
  3. Can all functions have inverses? Why or why not?
  4. What is the significance of the range and domain in real-world problems?
  5. How does a horizontal line test determine if a function is invertible?

Tip: Always remember that a function must be one-to-one (i.e., it passes the horizontal line test) in order to have an inverse.

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Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Inverse Functions

Formulas

f(x) = 3x + 5
f^{-1}(x) = (x - 5) / 3

Theorems

Inverse Function Theorem
Domain and Range of Linear Functions

Suitable Grade Level

Grades 10-12