Math Problem Statement

what is the limit as x approaches infinity f(x)= (x^5)/squareroot((x^10)+8)

Solution

We are tasked with finding the limit of the function f(x)=x5x10+8f(x) = \frac{x^5}{\sqrt{x^{10} + 8}} as xx approaches infinity.

Step-by-Step Solution

  1. Simplify the function for large xx:

    For very large xx, the x10x^{10} term inside the square root will dominate the constant 8. Hence, we can approximate x10+8x10=x5\sqrt{x^{10} + 8} \approx \sqrt{x^{10}} = x^5 for large xx. This is because as xx \to \infty, the constant becomes negligible compared to x10x^{10}.

    Now rewrite the function: f(x)=x5x10+8x5x10=x5x5f(x) = \frac{x^5}{\sqrt{x^{10} + 8}} \approx \frac{x^5}{\sqrt{x^{10}}} = \frac{x^5}{x^5}

  2. Limit of the simplified expression:

    After simplifying, we get: f(x)x5x5=1f(x) \approx \frac{x^5}{x^5} = 1

    Therefore, as xx \to \infty, the function tends toward 1.

Conclusion:

limxx5x10+8=1\lim_{x \to \infty} \frac{x^5}{\sqrt{x^{10} + 8}} = 1

Would you like further clarification or more details? Here are some related questions to deepen your understanding:

  1. How do we formally justify dropping the constant term in limits?
  2. What would happen if the exponent of xx in the numerator was different, say x6x^6?
  3. How can we generalize this approach for similar functions?
  4. What is the limit if we replace the constant 8 with another term involving xx?
  5. Can L'Hopital's rule be applied to this problem? Why or why not?

Tip: When dealing with limits at infinity, focusing on the dominant terms often simplifies the evaluation.

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Math Problem Analysis

Mathematical Concepts

Limits
Algebraic Simplification
Asymptotic Behavior

Formulas

lim (x → ∞) f(x) = (x^5) / sqrt((x^10) + 8)
Simplification for large x: sqrt(x^10 + 8) ≈ x^5

Theorems

Limit Theorem
Simplification of Dominant Terms

Suitable Grade Level

Grades 11-12