Math Problem Statement

Calculate the limits as x approaches infinity for the given expressions.

Solution

Let's solve these limits step by step.

1. limx11x8+2x\lim_{x \to \infty} \frac{-11x}{8 + 2x}

To find the limit as xx \to \infty, we divide both the numerator and the denominator by xx:

limx11x8+2x=limx118x+2\lim_{x \to \infty} \frac{-11x}{8 + 2x} = \lim_{x \to \infty} \frac{-11}{\frac{8}{x} + 2}

As xx \to \infty, 8x0\frac{8}{x} \to 0, so the expression simplifies to:

limx112=112\lim_{x \to \infty} \frac{-11}{2} = -\frac{11}{2}

2. limx13x7x3+4x10\lim_{x \to \infty} \frac{13x - 7}{x^3 + 4x - 10}

For this limit, we divide both the numerator and the denominator by x3x^3 (the highest power of xx in the denominator):

limx13x7x3+4x10=limx13x27x31+4x210x3\lim_{x \to \infty} \frac{13x - 7}{x^3 + 4x - 10} = \lim_{x \to \infty} \frac{\frac{13}{x^2} - \frac{7}{x^3}}{1 + \frac{4}{x^2} - \frac{10}{x^3}}

As xx \to \infty, all terms with xx in the denominator tend to 0:

limx0=0\lim_{x \to \infty} 0 = 0

3. limxx22x21115x2\lim_{x \to \infty} \frac{x^2 - 2x - 2}{11 - 15x^2}

Divide both the numerator and the denominator by x2x^2 (the highest power of xx):

limxx22x21115x2=limx12x2x211x215\lim_{x \to \infty} \frac{x^2 - 2x - 2}{11 - 15x^2} = \lim_{x \to \infty} \frac{1 - \frac{2}{x} - \frac{2}{x^2}}{\frac{11}{x^2} - 15}

As xx \to \infty, the terms involving xx in the denominator tend to 0, so we are left with:

115=115\frac{1}{-15} = -\frac{1}{15}

4. limxx2+14x63x\lim_{x \to \infty} \frac{\sqrt{x^2 + 14x}}{6 - 3x}

Factor out x2x^2 from inside the square root and divide both numerator and denominator by xx:

limxx2(1+14x)63x=limxx1+14x3x(163x)\lim_{x \to \infty} \frac{\sqrt{x^2(1 + \frac{14}{x})}}{6 - 3x} = \lim_{x \to \infty} \frac{x\sqrt{1 + \frac{14}{x}}}{-3x(1 - \frac{6}{3x})}

As xx \to \infty, 14x0\frac{14}{x} \to 0, so the expression simplifies to:

limxx3x=13\lim_{x \to \infty} \frac{x}{-3x} = -\frac{1}{3}

5. limxx2+14x63x\lim_{x \to \infty} \frac{\sqrt{x^2 + 14x}}{6 - 3x}

This is the same expression as the previous one, so the result is also:

13- \frac{1}{3}

Let me know if you'd like further clarification or more detailed steps. Here are some related questions:

  1. How do you determine which term dominates in a limit as xx \to \infty?
  2. Why does dividing by the highest power of xx simplify limits at infinity?
  3. How do we handle square roots in limit problems?
  4. What happens to constants as xx \to \infty?
  5. Can limits at infinity result in finite values even if the function grows without bound?

Tip: Always divide by the highest power of xx in limits involving polynomials to simplify the process of finding the behavior as xx \to \infty.

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Math Problem Analysis

Mathematical Concepts

Limits at Infinity
Rational Functions
Asymptotic Behavior
Simplification of Polynomials
Handling Square Roots in Limits

Formulas

Divide numerator and denominator by the highest power of x
Limit of rational functions as x approaches infinity
Simplification using L'Hopital's Rule (if applicable)

Theorems

Properties of Limits
Behavior of Polynomials at Infinity
Asymptotic Analysis

Suitable Grade Level

Grades 11-12, Early College