Math Problem Statement

Calculate the limit \( \lim_{{x \to 0}} \frac{\sin |x|}{x} \).

Solution

To solve the limit

limx0sinxx,\lim_{{x \to 0}} \frac{\sin |x|}{x},

we need to consider the behavior of the function as xx approaches 0 from both the left and right.

Step 1: Rewrite sinx\sin |x|

Since x|x| is always non-negative, we can observe that sinx\sin |x| will behave similarly to sinx\sin x around x=0x = 0. As x0x \to 0, x|x| also approaches 0.

Step 2: Apply Limit Properties

We can split the limit into two one-sided limits to analyze them separately:

  1. As x0+x \to 0^+: limx0+sinxx=limx0+sinxx=1.\lim_{{x \to 0^+}} \frac{\sin |x|}{x} = \lim_{{x \to 0^+}} \frac{\sin x}{x} = 1.

  2. As x0x \to 0^-: limx0sinxx=limx0sin(x)x=limx0sinxx=1.\lim_{{x \to 0^-}} \frac{\sin |x|}{x} = \lim_{{x \to 0^-}} \frac{\sin (-x)}{x} = \lim_{{x \to 0^-}} \frac{-\sin x}{x} = -1.

Step 3: Conclusion

The left-hand limit and the right-hand limit do not match:

  • limx0+sinxx=1\lim_{{x \to 0^+}} \frac{\sin |x|}{x} = 1,
  • limx0sinxx=1\lim_{{x \to 0^-}} \frac{\sin |x|}{x} = -1.

Since the two one-sided limits are not equal, the limit

limx0sinxx\lim_{{x \to 0}} \frac{\sin |x|}{x}

does not exist.

Would you like a more detailed breakdown of any specific part of this solution?

Here are some related questions to explore:

  1. What is the significance of absolute values in limit problems?
  2. How does the squeeze theorem apply to trigonometric limits?
  3. Can the limit exist if only one-sided limits are defined?
  4. How would this limit change if we removed the absolute value?
  5. How does the behavior of sine functions impact limits near zero?

Tip: When dealing with limits that involve absolute values, split the limit into one-sided cases to see if the behavior changes across the point of interest.

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Math Problem Analysis

Mathematical Concepts

Limits
Absolute Value
Trigonometric Functions

Formulas

\( \lim_{{x \to 0}} \frac{\sin x}{x} = 1 \)

Theorems

One-Sided Limits
Limit Existence Criterion

Suitable Grade Level

Undergraduate Calculus