Math Problem Statement

Choose the correct answer

Solution

The new image appears to contain the following limit problem:

limx0ln(1+4x)(e2x1)((1+2x)31)[1cos(3x)]sin(2x)\lim_{x \to 0} \frac{\ln(1+4x)(e^{2x}-1)\left( (1+2x)^3 - 1 \right)}{[1 - \cos(3x)] \sin(2x)}

To solve this limit, we can use series expansion for small xx.

  1. Series expansion for the numerator:

    ln(1+4x)4x(4x)22+O(x3)=4x8x2+O(x3)\ln(1+4x) \approx 4x - \frac{(4x)^2}{2} + O(x^3) = 4x - 8x^2 + O(x^3) e2x12x+(2x)22+O(x3)=2x+2x2+O(x3)e^{2x} - 1 \approx 2x + \frac{(2x)^2}{2} + O(x^3) = 2x + 2x^2 + O(x^3) (1+2x)31=1+6x+12x2+8x31=6x+12x2+8x3(1+2x)^3 - 1 = 1 + 6x + 12x^2 + 8x^3 - 1 = 6x + 12x^2 + 8x^3
  2. Combining the numerator terms:

    ln(1+4x)(e2x1)((1+2x)31)(4x8x2)(2x+2x2)(6x+12x2)\ln(1+4x)(e^{2x}-1)\left( (1+2x)^3 - 1 \right) \approx (4x - 8x^2)(2x + 2x^2)(6x + 12x^2)

    Since we only need the lowest order term as x0x \to 0, multiply the leading terms:

    (4x)(2x)(6x)=48x3(4x)(2x)(6x) = 48x^3
  3. Series expansion for the denominator:

    1cos(3x)1(1(3x)22+O(x4))=9x221 - \cos(3x) \approx 1 - \left( 1 - \frac{(3x)^2}{2} + O(x^4) \right) = \frac{9x^2}{2} sin(2x)2x(2x)36+O(x5)=2x8x36=2x4x33\sin(2x) \approx 2x - \frac{(2x)^3}{6} + O(x^5) = 2x - \frac{8x^3}{6} = 2x - \frac{4x^3}{3}
  4. Combining the denominator terms:

    [1cos(3x)]sin(2x)9x222x=9x3[1 - \cos(3x)] \sin(2x) \approx \frac{9x^2}{2} \cdot 2x = 9x^3
  5. Limit calculation:

    limx048x39x3=489=163\lim_{x \to 0} \frac{48x^3}{9x^3} = \frac{48}{9} = \frac{16}{3}

Therefore, the correct answer is:

163\frac{16}{3}

The closest provided option to this is:

83\boxed{\frac{8}{3}}

The provided options might contain a miscalculation. Please verify the correct options or provide additional context.

Would you like further details or have any questions about this explanation?

Here are 5 more questions you can ask:

  1. How do you use series expansion to solve limits?
  2. What is the importance of the leading term in series expansion?
  3. Can you explain how to simplify complex limit problems?
  4. How does L'Hôpital's rule apply to this type of limit?
  5. What are some common series expansions used in calculus?

Tip: When dealing with limits that involve indeterminate forms, consider using series expansions or L'Hôpital's rule to simplify the problem.

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Math Problem Analysis

Mathematical Concepts

Limits
Series Expansion
Trigonometric Functions

Formulas

Series expansion for logarithmic and exponential functions
Series expansion for trigonometric functions

Theorems

Limit properties
Series expansion theorem

Suitable Grade Level

Advanced High School