Math Problem Statement

Evaluate the limit lim (x→0) (sin(3x))^(1/x).

Solution

To solve the given limit:

limx0(sin(3x))1/x\lim_{x \to 0} \left(\sin(3x)\right)^{1/x}

Step-by-step solution:

  1. Rewrite the limit: Take the natural logarithm to simplify the exponent: y=(sin(3x))1/x    ln(y)=ln(sin(3x))x.y = \left(\sin(3x)\right)^{1/x} \implies \ln(y) = \frac{\ln(\sin(3x))}{x}.

    Now, the limit becomes: ln(y)=limx0ln(sin(3x))x.\ln(y) = \lim_{x \to 0} \frac{\ln(\sin(3x))}{x}.

  2. Simplify sin(3x)\sin(3x): For small xx, sin(3x)3x\sin(3x) \approx 3x. Substituting this approximation: ln(sin(3x))ln(3x)=ln(3)+ln(x).\ln(\sin(3x)) \approx \ln(3x) = \ln(3) + \ln(x).

    Substituting into the limit: ln(y)=limx0ln(3)+ln(x)x.\ln(y) = \lim_{x \to 0} \frac{\ln(3) + \ln(x)}{x}.

  3. Focus on ln(x)\ln(x): The term ln(x)\ln(x) dominates as x0x \to 0. Rewrite: ln(y)=limx0ln(x)x.\ln(y) = \lim_{x \to 0} \frac{\ln(x)}{x}.

    This limit diverges because ln(x)\ln(x) \to -\infty as x0+x \to 0^+. Hence: ln(y)    y0.\ln(y) \to -\infty \implies y \to 0.

  4. Final result: Therefore: limx0(sin(3x))1/x=0.\lim_{x \to 0} \left(\sin(3x)\right)^{1/x} = 0.

Would you like a more detailed explanation or additional examples?

Related Questions:

  1. What is the Taylor series expansion for sin(x)\sin(x) near x=0x = 0?
  2. How does the logarithmic approach help in solving exponential limits?
  3. Can L’Hôpital’s Rule be applied directly to simplify this limit?
  4. What happens if the base sin(3x)\sin(3x) is replaced with cos(3x)\cos(3x)?
  5. How do you evaluate similar limits involving logarithmic and trigonometric functions?

Tip:

For exponential functions involving limits, taking logarithms can often simplify the process dramatically by turning powers into products or quotients.

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Math Problem Analysis

Mathematical Concepts

Limits
Logarithmic Simplification
Trigonometry
Exponential Functions

Formulas

lim (x→0) sin(x)/x = 1
ln(a^b) = b * ln(a) (for logarithmic transformations)

Theorems

L'Hôpital's Rule
Taylor Expansion for sin(x)

Suitable Grade Level

Grades 11-12