Math Problem Statement

y = e−x − 2 range and domain

Solution

Let's find the domain and range of the function y=ex2y = e^{-x} - 2.

1. Domain:

The domain of a function consists of all the possible input values (xx) for which the function is defined.

  • The expression exe^{-x} (an exponential function) is defined for all real numbers xx.
  • Therefore, there are no restrictions on xx.

Thus, the domain of y=ex2y = e^{-x} - 2 is:

(,)\boxed{(-\infty, \infty)}

2. Range:

The range consists of all the possible output values (yy) that the function can produce.

  • The function exe^{-x} is always positive for any real number xx, and exe^{-x} can approach 0 as xx tends to infinity, but it never reaches 0. Therefore, ex>0e^{-x} > 0 for all xx.
  • Now, y=ex2y = e^{-x} - 2 subtracts 2 from exe^{-x}, meaning:
    • The minimum value of exe^{-x} approaches 0 as xx becomes very large, so yy approaches 2-2.
    • The maximum value of exe^{-x} is 1 when x=0x = 0, so y=12=1y = 1 - 2 = -1.

Thus, the function will never reach 2-2 but can get infinitely close to it, and it can take values less than 1-1.

Therefore, the range of the function is:

(2,)\boxed{(-2, \infty)}


Would you like more details or have any questions on this? Here are 5 related questions to expand on this:

  1. How would the domain and range change if the function was y=ex+2y = e^{-x} + 2?
  2. What is the graph of the function y=ex2y = e^{-x} - 2 like, and how does it behave as xx \to \infty and xx \to -\infty?
  3. Can you determine the horizontal asymptote for this function?
  4. What would be the domain and range of y=ex2y = -e^{-x} - 2?
  5. How would the function change if the exponent in exe^{-x} were positive, like in ex2e^x - 2?

Tip: Exponential functions always have horizontal asymptotes, which can help determine their range.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Domain and Range

Formulas

y = e^{-x} - 2
Domain: (-∞, ∞)
Range: (-2, ∞)

Theorems

Exponential Function Properties
Domain and Range Determination

Suitable Grade Level

Grades 10-12