Math Problem Statement

Evaluate the following expression: \left( \lim_{{x \to 1}} \frac{{x^2 - 64}}{{x - 8}} \right)^3 + \left( \lim_{{x \to \infty}} \frac{{8x^2 - 5x}}{{x^2}} \right)^2 + \lim_{{x \to 0}} \frac{{e^{13x} - 1}}{{x}}

Solution

The image contains the following limit expression:

(limx1x264x8)3+(limx8x25xx2)2+limx0e13x1x\left( \lim_{{x \to 1}} \frac{{x^2 - 64}}{{x - 8}} \right)^3 + \left( \lim_{{x \to \infty}} \frac{{8x^2 - 5x}}{{x^2}} \right)^2 + \lim_{{x \to 0}} \frac{{e^{13x} - 1}}{{x}}

Let's break it down and calculate each limit:

  1. First Limit: limx1x264x8\lim_{{x \to 1}} \frac{{x^2 - 64}}{{x - 8}}

We can factor x264x^2 - 64 as (x8)(x+8)(x - 8)(x + 8): limx1(x8)(x+8)x8=limx1(x+8)\lim_{{x \to 1}} \frac{{(x - 8)(x + 8)}}{{x - 8}} = \lim_{{x \to 1}} (x + 8) Substituting x=1x = 1: 1+8=91 + 8 = 9 So, this limit evaluates to 9.

  1. Second Limit: limx8x25xx2\lim_{{x \to \infty}} \frac{{8x^2 - 5x}}{{x^2}}

We can divide each term by x2x^2: limx(85x)\lim_{{x \to \infty}} \left( 8 - \frac{5}{x} \right) As xx \to \infty, 5x0\frac{5}{x} \to 0, so the limit is: 88

  1. Third Limit: limx0e13x1x\lim_{{x \to 0}} \frac{{e^{13x} - 1}}{{x}}

This is a standard limit, which is recognized as the derivative of e13xe^{13x} at x=0x = 0. Using the known result: limx0e13x1x=13\lim_{{x \to 0}} \frac{{e^{13x} - 1}}{{x}} = 13

Now, combining all three parts: (9)3+(8)2+13=729+64+13=806\left( 9 \right)^3 + \left( 8 \right)^2 + 13 = 729 + 64 + 13 = 806

Thus, the value of the entire expression is: 806806

Would you like further details or explanations for any of the steps? Here are some related questions you might find helpful:

  1. What is the formal definition of a limit?
  2. How do you evaluate indeterminate forms like 00\frac{0}{0}?
  3. How can you use L'Hopital's rule to simplify limits?
  4. What is the derivative of e13xe^{13x}, and how does it relate to the third limit?
  5. How does factoring help when evaluating limits involving polynomials?

Tip: When dealing with limits of polynomials, always look for opportunities to factor expressions, especially when direct substitution results in indeterminate forms.

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Math Problem Analysis

Mathematical Concepts

Limits
Factorization
Exponential Functions
Infinity Behavior

Formulas

Factorization: x^2 - a^2 = (x - a)(x + a)
Limit of exponential functions: \lim_{x \to 0} \frac{e^{kx} - 1}{x} = k
Limit of rational functions at infinity: \lim_{x \to \infty} \frac{ax^2 + bx + c}{dx^2 + ex + f}

Theorems

Limit laws
Derivatives of exponential functions
Limit at infinity behavior

Suitable Grade Level

Grades 11-12