Math Problem Statement

What are the domain and range of f(x) = -log_5(x + 2)?

Solution

The question asks for the domain and range of the function f(x)=log5(x+2)f(x) = -\log_5(x + 2).

Domain:

  • The logarithmic function logb(x)\log_b(x) is only defined for x>0x > 0. For this particular function, log5(x+2)\log_5(x + 2), the argument x+2x + 2 must be greater than 0.
    • So, x+2>0x + 2 > 0 implies x>2x > -2.
    • Therefore, the domain is x>2x > -2.

Range:

  • The function f(x)=log5(x+2)f(x) = -\log_5(x + 2) involves a logarithmic expression. The logarithmic function typically has a range of all real numbers, but since there's a negative sign in front of the logarithm, it reflects the graph across the x-axis.
    • Thus, the range remains all real numbers.

Conclusion:

The correct answer is: A: Domain: x>2x > -2, Range: all real numbers.

Would you like a detailed explanation or further clarifications?

Here are 5 related questions for further exploration:

  1. How do you determine the domain of any logarithmic function?
  2. What happens to the range of a function if it is multiplied by a negative number?
  3. How would the domain and range change if the function was log(x3)\log(x - 3)?
  4. What is the effect of different logarithmic bases on the graph of a logarithmic function?
  5. How does a horizontal or vertical shift affect the domain of logarithmic functions?

Tip: Remember, the domain of a logarithmic function is always determined by the condition that the argument of the logarithm must be strictly greater than zero.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Functions
Domain and Range

Formulas

f(x) = -log_b(x)
Domain condition: x + 2 > 0

Theorems

Properties of Logarithmic Functions
Reflection of Functions

Suitable Grade Level

Grades 9-11