Math Problem Statement

Let f(x) = (x - 1)^2. Find a domain on which f is one-to-one and non-decreasing. Find the inverse of f restricted to this domain.

Solution

The question in the image asks the following:

  1. Let f(x)=(x1)2f(x) = (x - 1)^2.
    • Find a domain where ff is one-to-one and non-decreasing.
    • Find the inverse of ff restricted to this domain.

Step 1: Finding a Domain Where f(x)f(x) is One-to-One and Non-Decreasing

The function f(x)=(x1)2f(x) = (x - 1)^2 is a parabola, which opens upwards (since the coefficient of x2x^2 is positive). A parabola is not one-to-one over its entire domain because it is symmetric around its vertex. The vertex of f(x)=(x1)2f(x) = (x - 1)^2 is at x=1x = 1.

To make the function one-to-one, we need to restrict the domain to either the left or right of the vertex. Since the question asks for a domain where the function is non-decreasing, we choose the interval where f(x)f(x) is increasing. This happens for x1x \geq 1.

Thus, the domain on which f(x)f(x) is one-to-one and non-decreasing is: x1x \geq 1

Step 2: Finding the Inverse of f(x)f(x) on the Restricted Domain

To find the inverse, we start with the equation for f(x)f(x): y=(x1)2y = (x - 1)^2 Now, solve for xx in terms of yy: y=x1\sqrt{y} = x - 1 x=y+1x = \sqrt{y} + 1 Since the domain is restricted to x1x \geq 1, we take the positive square root.

Thus, the inverse function is: f1(x)=x+1f^{-1}(x) = \sqrt{x} + 1

Final Answer:

  1. The domain where ff is one-to-one and non-decreasing: x1x \geq 1.
  2. The inverse of ff restricted to this domain: f1(x)=x+1f^{-1}(x) = \sqrt{x} + 1.

Would you like more details or have any questions?

Here are five related questions to deepen your understanding:

  1. How do we determine the vertex of a quadratic function?
  2. Why is a function not one-to-one over its entire domain if it is symmetric?
  3. Can the domain restriction be x1x \leq 1 instead, and if so, how would the inverse change?
  4. What is the general method for finding the inverse of a function?
  5. How does restricting the domain of a function affect its graph?

Tip: When finding the inverse of a quadratic function, always be mindful of domain restrictions, as a quadratic function is not naturally one-to-one.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Inverse Functions
Domain Restrictions

Formulas

f(x) = (x - 1)^2
f^{-1}(x) = √x + 1

Theorems

A function is one-to-one if it passes the Horizontal Line Test
Quadratic functions are not one-to-one unless their domains are restricted

Suitable Grade Level

Grades 10-12