Math Problem Statement

find the domain and range of a f(x)=3x-2/x²

Solution

Let's analyze the function f(x)=3x2x2f(x) = \frac{3x - 2}{x^2} to determine its domain and range.

Domain:

The domain of a function consists of all the values of xx for which the function is defined.

For f(x)=3x2x2f(x) = \frac{3x - 2}{x^2}, the function is undefined when the denominator is zero. The denominator here is x2x^2, and x2=0x^2 = 0 when x=0x = 0.

Thus, the function is undefined at x=0x = 0.

Domain: xR{0}x \in \mathbb{R} \setminus \{0\}, or in interval notation: (,0)(0,)(-\infty, 0) \cup (0, \infty).

Range:

To find the range, we analyze the behavior of the function as xx varies over its domain.

  1. For large positive or negative values of xx, f(x)f(x) behaves approximately like 3xx2=3x\frac{3x}{x^2} = \frac{3}{x}, which approaches 0 as xx tends to ±\pm\infty.

  2. Near x=0x = 0, the function's behavior depends on whether xx approaches 0 from the positive side or the negative side:

    • As x0+x \to 0^+ (from the right), x2x^2 is small and positive, making f(x)f(x) large and positive.
    • As x0x \to 0^- (from the left), x2x^2 is still small and positive, but the numerator 3x23x - 2 is negative, so f(x)f(x) becomes large and negative.

This suggests that the function can take any real value as xx approaches 0 from either side and as xx tends to ±\pm\infty.

Range: f(x)Rf(x) \in \mathbb{R}, or in interval notation: (,)(-\infty, \infty).

Summary:

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

Would you like more details or have any questions?

Here are some related questions:

  1. What happens if the numerator of a rational function is zero?
  2. How does the behavior of a function near a vertical asymptote affect its range?
  3. How can the domain of a function change if the expression is more complex, like a square root?
  4. Can a function have a restricted range even if its domain is all real numbers?
  5. What is the impact of adding or subtracting constants on the domain and range of a function?

Tip: Always check for undefined points in a function's domain, especially where the denominator equals zero or inside square roots and logarithms.

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Domain and Range

Formulas

Function domain criteria
Analysis of rational functions

Theorems

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Suitable Grade Level

High School