Math Problem Statement

Determine the limit: lim (x → -∞) [6 exp(-x + 8) + 2]

Solution

We are tasked with determining the limit:

limx(6exp(x+8)+2)\lim_{x \to -\infty} \left( 6 \exp(-x + 8) + 2 \right)

Solution:

First, we simplify the exponential term:

exp(x+8)=exp(x)exp(8)\exp(-x + 8) = \exp(-x) \cdot \exp(8)

Since exp(8)\exp(8) is just a constant, we now focus on the behavior of exp(x)\exp(-x) as xx \to -\infty.

  • When xx \to -\infty, exp(x)\exp(-x) behaves as follows: exp(x)=exe+=\exp(-x) = e^{-x} \to e^{+\infty} = \infty

Thus, the entire expression for the exponential grows without bound as xx \to -\infty. Therefore:

6exp(x+8)6=6 \exp(-x + 8) \to 6 \cdot \infty = \infty

Finally, since the added constant 22 does not affect the infinity, the entire limit becomes:

limx(6exp(x+8)+2)=\lim_{x \to -\infty} \left( 6 \exp(-x + 8) + 2 \right) = \infty

Thus, the limit is \infty.

Would you like more details or have any questions?

Here are 5 related questions for further exploration:

  1. How does the behavior of exp(x)\exp(x) change as xx \to \infty compared to xx \to -\infty?
  2. What is the limit of 6exp(x+8)6 \exp(-x + 8) as xx \to \infty?
  3. How does adding or subtracting constants inside the exponential affect the function's growth?
  4. How do limits involving exponential functions differ from polynomial limits as xx \to \infty?
  5. Can you think of other functions where limits as xx \to -\infty behave similarly?

Tip: When evaluating limits at infinity, always check the dominant term. In this case, the exponential grows much faster than any constant term.

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Math Problem Analysis

Mathematical Concepts

Limits
Exponential Functions

Formulas

lim (x → -∞) 6 exp(-x + 8) + 2
exp(a + b) = exp(a) * exp(b)
lim (x → -∞) exp(-x) = ∞

Theorems

Limit properties of exponential functions at infinity

Suitable Grade Level

Grades 11-12 (or Pre-University)