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limni=1n16in2\lim_{n \to \infty}\sum_{i=1}^{n}\frac{16i}{n^{2}}

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Q. limni=1n16in2\lim_{n \to \infty}\sum_{i=1}^{n}\frac{16i}{n^{2}}
  1. Recognize Riemann Sum: We recognize that the given series is a Riemann sum. The Riemann sum is used to approximate the integral of a function over an interval by partitioning the interval and summing up areas of rectangles under the curve. The general form of a Riemann sum is i=1nf(xi)(Δx)\sum_{i=1}^{n}f(x_i)\cdot(\Delta x), where Δx\Delta x is the width of each partition and f(xi)f(x_i) is the function value at the iith partition. In our case, f(xi)=16xf(x_i) = 16x, and Δx=1n\Delta x = \frac{1}{n}. We can rewrite the series as i=1n(16in2)=i=1n(16n2)i\sum_{i=1}^{n}\left(\frac{16i}{n^2}\right) = \sum_{i=1}^{n}\left(\frac{16}{n^2}\right)\cdot i. Here, 16n2\frac{16}{n^2} is constant for each term in the sum, and ii represents the iith partition's contribution to the sum.
  2. Express as Riemann Sum: We can now express the sum as a Riemann sum that approximates the integral of the function f(x)=16xf(x) = 16x from 00 to 11 as nn approaches infinity. The Riemann sum becomes limn(16n2)i=1ni\lim_{n \to \infty}(\frac{16}{n^2}) \cdot \sum_{i=1}^{n}i. The sum i=1ni\sum_{i=1}^{n}i is the sum of the first nn natural numbers, which can be calculated using the formula n(n+1)2\frac{n(n+1)}{2}.
  3. Substitute Formula: Substitute the formula for the sum of the first nn natural numbers into the Riemann sum: limn(16n2)(n(n+1)2)\lim_{n \to \infty}\left(\frac{16}{n^2}\right) * \left(\frac{n(n+1)}{2}\right). This simplifies to limn(16n2)(n22+n2)\lim_{n \to \infty}\left(\frac{16}{n^2}\right) * \left(\frac{n^2}{2} + \frac{n}{2}\right).
  4. Distribute Terms: Distribute 16n2\frac{16}{n^2} across the terms in the parentheses: limn(162+16n2n2)\lim_{n \rightarrow \infty}\left(\frac{16}{2} + \frac{16n}{2n^2}\right). This simplifies to limn(8+8n)\lim_{n \rightarrow \infty}\left(8 + \frac{8}{n}\right).
  5. Take Limit: Now, take the limit as nn approaches infinity. The term 8n\frac{8}{n} approaches 00 as nn becomes very large, so the limit is limn(8+8n)=8+0\lim_{n \rightarrow \infty}(8 + \frac{8}{n}) = 8 + 0.
  6. Final Answer: The final answer is the limit of the sum, which is 88. This is the value of the integral of f(x)=16xf(x) = 16x from 00 to 11.

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