Math Problem Statement

f(x) = x²/1-x² find domain and range

Solution

To determine the domain and range of the function f(x)=x21x2f(x) = \frac{x^2}{1 - x^2}, we need to consider where the function is defined and the set of possible output values.

Domain

The domain of the function is the set of all xx values for which the function is defined. The function f(x)=x21x2f(x) = \frac{x^2}{1 - x^2} has a denominator 1x21 - x^2. The denominator cannot be zero because division by zero is undefined. Therefore, we need to find where 1x2=01 - x^2 = 0:

1x2=01 - x^2 = 0 x2=1x^2 = 1 x=±1x = \pm 1

Thus, the function is undefined at x=1x = 1 and x=1x = -1. Therefore, the domain is all real numbers except x=1x = 1 and x=1x = -1:

Domain: x(,1)(1,1)(1,)\text{Domain: } x \in (-\infty, -1) \cup (-1, 1) \cup (1, \infty)

Range

To find the range, we analyze the behavior of the function:

  1. As xx approaches 00, f(x)f(x) approaches 00.
  2. As xx approaches 11 from the left, f(x)f(x) approaches ++\infty.
  3. As xx approaches 11 from the right, f(x)f(x) approaches -\infty.
  4. As xx approaches 1-1 from the left, f(x)f(x) approaches ++\infty.
  5. As xx approaches 1-1 from the right, f(x)f(x) approaches -\infty.
  6. For large positive or negative values of xx, f(x)f(x) approaches 1-1.

Next, we solve for yy in terms of xx:

y=x21x2y = \frac{x^2}{1 - x^2} y(1x2)=x2y(1 - x^2) = x^2 yyx2=x2y - yx^2 = x^2 y=x2(1+y)y = x^2(1 + y) x2=y1+yx^2 = \frac{y}{1 + y}

For x2x^2 to be non-negative, y1+y0\frac{y}{1 + y} \geq 0. This implies y0y \geq 0 or y1y \leq -1.

Therefore, the range of the function is:

Range: (,1][0,)\text{Range: } (-\infty, -1] \cup [0, \infty)

Summary

  • Domain: (,1)(1,1)(1,)(-\infty, -1) \cup (-1, 1) \cup (1, \infty)
  • Range: (,1][0,)(-\infty, -1] \cup [0, \infty)

Would you like more details or have any questions?

Here are 5 numbered questions for you to ask:

  1. How do you find the domain of a function involving a square root?
  2. What is the range of the function f(x)=1xf(x) = \frac{1}{x}?
  3. How do you find the asymptotes of a rational function?
  4. Can you explain how to determine the inverse of a function?
  5. What is the domain of the function g(x)=x2g(x) = \sqrt{x - 2}?

Tip: When finding the domain of a function, always look for values that make the denominator zero or the argument of a square root negative.

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Math Problem Analysis

Mathematical Concepts

Functions
Rational Functions
Domain and Range

Formulas

Function definition
Quadratic equation

Theorems

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Suitable Grade Level

Grades 11-12