Math Problem Statement

imagine answering this on exam: give the complete solution and answer for the range of the given y = (1/5)^x

Solution

To find the range of the function y=(15)xy = \left(\frac{1}{5}\right)^x, we can follow a systematic process.

Step 1: Analyze the Behavior of the Function

The function y=(15)xy = \left(\frac{1}{5}\right)^x is an exponential function where the base is a positive fraction 15\frac{1}{5}. This means the function will behave differently compared to those with bases greater than 1 (like 2x2^x or 3x3^x).

Step 2: Identify Key Characteristics of the Function

  • As x+x \to +\infty (i.e., as xx increases to large positive values), the value of (15)x\left(\frac{1}{5}\right)^x becomes smaller and approaches zero.
  • As xx \to -\infty (i.e., as xx decreases to large negative values), the value of (15)x\left(\frac{1}{5}\right)^x increases because the base 15\frac{1}{5} raised to negative powers becomes larger than 1. Specifically, (15)x=5x\left(\frac{1}{5}\right)^x = 5^{-x}, and as xx gets more negative, 5x5^{-x} \to \infty.

Step 3: Examine the Range

  • The function approaches 0 as x+x \to +\infty, but never actually reaches 0. It just gets arbitrarily close to 0 from above.
  • As xx \to -\infty, the function grows without bound, approaching infinity.

Therefore, the range of the function y=(15)xy = \left(\frac{1}{5}\right)^x is all positive real numbers greater than 0. In interval notation, this is:

(0,)(0, \infty)

Conclusion:

The range of the function y=(15)xy = \left(\frac{1}{5}\right)^x is (0,)\boxed{(0, \infty)}.


Would you like more details on any part of the solution? Or would you like me to explain any concept further?

Here are some related questions to explore:

  1. How does the range change if the base of the exponential function is greater than 1, e.g., y=2xy = 2^x?
  2. What happens to the range if the base is negative, such as y=(2)xy = (-2)^x?
  3. How does the range of an exponential function differ from a logarithmic function?
  4. What is the range of the function y=5xy = 5^x and how does it compare to y=(15)xy = \left(\frac{1}{5}\right)^x?
  5. How can we graph the function y=(15)xy = \left(\frac{1}{5}\right)^x and visualize its range?

Tip: When dealing with exponential functions where the base is between 0 and 1 (like 15\frac{1}{5}), the function will always decrease as xx increases, and will approach 0 from above as x+x \to +\infty.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Function Range
Behavior of Exponential Functions

Formulas

y = (1/5)^x

Theorems

Exponential Function Behavior
Range of Exponential Functions

Suitable Grade Level

Grades 9-12