Math Problem Statement

Prove that \( \lim_{x \to 0^+} \sqrt{x} e^{\sin(\pi/x)} = 0 \).

Solution

To prove that

limx0+xesin(π/x)=0,\lim_{x \to 0^+} \sqrt{x} \, e^{\sin(\pi/x)} = 0,

we need to analyze the behavior of each component of the expression as x0+x \to 0^+.

Step-by-Step Solution

  1. Analyze x\sqrt{x} as x0+x \to 0^+:

    As x0+x \to 0^+, we see that x0\sqrt{x} \to 0. This suggests that x\sqrt{x} will tend to zero, which might make the entire expression go to zero. However, we must also consider the behavior of the exponential term esin(π/x)e^{\sin(\pi/x)}.

  2. Analyze esin(π/x)e^{\sin(\pi/x)} as x0+x \to 0^+:

    As x0+x \to 0^+, the term sin(π/x)\sin(\pi/x) oscillates between 1-1 and 11 because π/x\pi/x grows without bound and causes the sine function to oscillate rapidly. Therefore, 1sin(π/x)1.-1 \leq \sin(\pi/x) \leq 1. This gives bounds on esin(π/x)e^{\sin(\pi/x)}: e1esin(π/x)e1.e^{-1} \leq e^{\sin(\pi/x)} \leq e^1. Thus, esin(π/x)e^{\sin(\pi/x)} is bounded as x0+x \to 0^+, staying within the range [e1,e][e^{-1}, e].

  3. Combine the Results:

    Now we can combine these observations: xesin(π/x).\sqrt{x} \, e^{\sin(\pi/x)}. Since x0\sqrt{x} \to 0 as x0+x \to 0^+ and esin(π/x)e^{\sin(\pi/x)} is bounded (it does not diverge as x0+x \to 0^+), the product xesin(π/x)\sqrt{x} \, e^{\sin(\pi/x)} will also tend to zero.

  4. Conclusion:

    By the Squeeze Theorem, we conclude that limx0+xesin(π/x)=0.\lim_{x \to 0^+} \sqrt{x} \, e^{\sin(\pi/x)} = 0.

Final Answer

limx0+xesin(π/x)=0.\lim_{x \to 0^+} \sqrt{x} \, e^{\sin(\pi/x)} = 0.

Would you like a deeper explanation on any part of this solution, or do you have any questions?


Here are some related questions for further exploration:

  1. How does the Squeeze Theorem work, and when is it used in limit problems?
  2. What happens if we replace sin(π/x)\sin(\pi/x) with a different oscillatory function, like cos(π/x)\cos(\pi/x)?
  3. How would the limit change if x\sqrt{x} were replaced by xnx^n for some power nn?
  4. What are some examples of limits where the exponential function plays a critical role?
  5. How do bounded functions interact with terms that approach zero in limits?

Tip: In limit problems, if one term approaches zero and the other is bounded, the entire expression often tends to zero.

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Math Problem Analysis

Mathematical Concepts

Limits
Exponentials
Oscillatory Functions
Squeeze Theorem

Formulas

\( \lim_{x \to 0^+} \sqrt{x} e^{\sin(\pi/x)} \)
Bounds: \( e^{-1} \leq e^{\sin(\pi/x)} \leq e^1 \)

Theorems

Squeeze Theorem

Suitable Grade Level

Undergraduate Calculus