Math Problem Statement

Use the Squeeze Theorem to evaluate the limit: lim_{x->0+} (sqrt(3x) * e^{cos(8pi/x)}).

Solution

To solve the limit using the Squeeze Theorem, let's first express the limit in a more manageable form. We are given:

limx0+3xecos(8πx)\lim_{x \to 0^+} \sqrt{3x} \cdot e^{\cos\left(\frac{8\pi}{x}\right)}

Step 1: Analyzing the components of the expression

  1. 3x\sqrt{3x}:

    • As xx approaches 0 from the right, 3x\sqrt{3x} approaches 0.
  2. ecos(8πx)e^{\cos\left(\frac{8\pi}{x}\right)}:

    • The term cos(8πx)\cos\left(\frac{8\pi}{x}\right) oscillates between 1-1 and 11 as xx approaches 0 because cos(θ)\cos(\theta) always lies between 1-1 and 11 for any θ\theta.
    • Thus, ecos(8πx)e^{\cos\left(\frac{8\pi}{x}\right)} oscillates between e1e^{-1} and e1e^1.

Step 2: Applying the Squeeze Theorem

Since e1ecos(8πx)ee^{-1} \leq e^{\cos\left(\frac{8\pi}{x}\right)} \leq e, we can write:

3xe13xecos(8πx)3xe\sqrt{3x} \cdot e^{-1} \leq \sqrt{3x} \cdot e^{\cos\left(\frac{8\pi}{x}\right)} \leq \sqrt{3x} \cdot e

Now, consider the limits of the bounding functions as x0+x \to 0^+:

limx0+3xe1=e1limx0+3x=0\lim_{x \to 0^+} \sqrt{3x} \cdot e^{-1} = e^{-1} \cdot \lim_{x \to 0^+} \sqrt{3x} = 0

limx0+3xe=elimx0+3x=0\lim_{x \to 0^+} \sqrt{3x} \cdot e = e \cdot \lim_{x \to 0^+} \sqrt{3x} = 0

Conclusion:

Since both bounds approach 0 as x0+x \to 0^+, by the Squeeze Theorem, the original limit also approaches 0.

limx0+3xecos(8πx)=0\lim_{x \to 0^+} \sqrt{3x} \cdot e^{\cos\left(\frac{8\pi}{x}\right)} = 0

Would you like further details or have any other questions?

Here are some related questions for further exploration:

  1. What is the Squeeze Theorem and how is it applied in different types of limits?
  2. How does the behavior of oscillating functions affect limits?
  3. Can the Squeeze Theorem be applied to non-oscillating functions?
  4. What are some examples of limits that require the Squeeze Theorem for evaluation?
  5. How does the exponential function behave when its exponent is oscillating?

Tip: When dealing with limits involving oscillating functions, consider the Squeeze Theorem to evaluate the behavior of the function at the limit point.

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Oscillating Functions

Formulas

Squeeze Theorem
Limit formula for oscillating functions

Theorems

Squeeze Theorem

Suitable Grade Level

College