Math Problem Statement

Determine the function and region whose area is equal to the given limit: lim_{n → ∞} ∑_{i=1}^{7} (49 - 49 / (12 + x_i^2)) / n.

Solution

The problem in the image asks to determine the function f(x)f(x) and region whose area is equal to the given limit expression. The provided options for f(x)f(x) include different functions, and the interval 0x70 \leq x \leq 7 appears to be relevant.

The limit in the question is represented as:

limni=17494912+xi2n\lim_{n \to \infty} \sum_{i=1}^{7} \frac{49 - \frac{49}{12+x_i^2}}{n}

This looks like a Riemann sum, which approximates the area under a curve by dividing the region into small sub-intervals. The function being summed over seems to be based on 12+x2\sqrt{12 + x^2}, indicating that the integral will involve this function over a specific range.

From the choices provided:

  • Option A: f(x)=12+x24f(x) = \frac{\sqrt{12 + x^2}}{4}, for 0x70 \leq x \leq 7
  • Option B: No Answer is correct
  • Option C: f(x)=49+x27x0f(x) = \sqrt{49 + x^2} - 7 \leq x \leq 0
  • Option D: f(x)=12+x2f(x) = \sqrt{12 + x^2}, for 0x70 \leq x \leq 7
  • Option E: f(x)=12+x2,0x7f(x) = \sqrt{12 + x^2}, 0 \leq x \leq 7

Approach:

  1. Interpret the limit as a Riemann sum for the integral.
  2. Check if the given function matches the Riemann sum's integrand, which is likely 12+x2\sqrt{12 + x^2}.
  3. Compare this with the provided options.

The function inside the sum seems closest to the form in Option D and E. Specifically, f(x)=12+x2f(x) = \sqrt{12 + x^2} for 0x70 \leq x \leq 7 is a plausible match, and the integral likely computes the area under this curve.

Thus, the correct choice appears to be Option D or E, depending on the formatting of the intervals.

Would you like further details on the solution, or have any follow-up questions?

Related questions:

  1. What is the process of converting a Riemann sum to a definite integral?
  2. How do you compute the definite integral of 12+x2\sqrt{12 + x^2}?
  3. What is the importance of limits in defining Riemann sums?
  4. How is the choice of f(x)f(x) related to the integrand in the Riemann sum?
  5. Can the area under different functions be computed similarly using Riemann sums?

Tip:

When dealing with limits and sums, always check if they represent a Riemann sum, as this can often be converted into an integral for easier calculation.

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Math Problem Analysis

Mathematical Concepts

Riemann Sum
Integral Calculus
Area Under a Curve
Limits

Formulas

Riemann Sum: lim_{n → ∞} ∑_{i=1}^{n} f(x_i) Δx
Integral of a square root function: ∫ sqrt(12 + x^2) dx

Theorems

Riemann Sum Theorem: A Riemann sum can approximate the area under a curve, which is the integral of a function.
Limit Theorem: The limit of a sum as n approaches infinity can be interpreted as a definite integral.

Suitable Grade Level

Undergraduate level (Calculus I or II)