Math Problem Statement

(\lim _{x\rightarrow \infty }(\sqrt{\frac{\left(8x^{2}-3\right)}{\left(2x^{2}+x\right)}}))

Solution

We are tasked with finding the limit:

limx8x232x2+x\lim_{x \to \infty} \sqrt{\frac{8x^2 - 3}{2x^2 + x}}

Step 1: Simplify the expression inside the square root.

The expression inside the square root is:

8x232x2+x\frac{8x^2 - 3}{2x^2 + x}

To handle limits as xx \to \infty, it helps to factor out the highest power of xx from both the numerator and the denominator. In this case, x2x^2 is the highest power.

8x232x2+x=x2(83x2)x2(2+1x)\frac{8x^2 - 3}{2x^2 + x} = \frac{x^2(8 - \frac{3}{x^2})}{x^2(2 + \frac{1}{x})}

Now, we can cancel out x2x^2 from both the numerator and the denominator:

=83x22+1x= \frac{8 - \frac{3}{x^2}}{2 + \frac{1}{x}}

Step 2: Take the limit as xx \to \infty.

As xx \to \infty, the terms 3x2\frac{3}{x^2} and 1x\frac{1}{x} approach 0. Therefore, the expression simplifies to:

802+0=82=4\frac{8 - 0}{2 + 0} = \frac{8}{2} = 4

Step 3: Apply the square root.

Now, apply the square root to the result:

4=2\sqrt{4} = 2

Final Answer:

limx8x232x2+x=2\lim_{x \to \infty} \sqrt{\frac{8x^2 - 3}{2x^2 + x}} = 2

Would you like further details or explanations on any of the steps?

Here are 5 related questions you might explore:

  1. How would the limit change if the coefficient of x2x^2 in the numerator were different?
  2. What is the effect of the lower degree terms like xx and constants on limits at infinity?
  3. How do square roots interact with limits in general?
  4. What if xx \to -\infty instead of xx \to \infty for this limit?
  5. How do you handle limits of more complicated expressions involving polynomials?

Tip: When calculating limits at infinity, focus on the highest degree terms, as they dominate the behavior of the function.

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Math Problem Analysis

Mathematical Concepts

Limits
Polynomials
Square Roots

Formulas

\lim_{x \to \infty} \frac{ax^n + bx^{n-1} + ...}{cx^n + dx^{n-1} + ...}
Square Root Function

Theorems

Limits of Rational Functions at Infinity
Simplification of Polynomials in Limits

Suitable Grade Level

Grades 11-12