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Ch. 5 - Integration
Briggs - Calculus: Early Transcendentals 3rd Edition
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5장, 문제 5.1.69a

Approximating areas Estimate the area of the region bounded by the graph of ƒ(𝓍) = x² + 2 and the x-axis on [0, 2] in the following ways.
(a) Divide [0, 2] into n = 4 subintervals and approximate the area of the region using a left Riemann sum. Illustrate the solution geometrically.

검증된 단계별 안내
1
First, divide the interval [0, 2] into 4 equal subintervals. Since the length of the interval is 2, each subinterval will have width \(\Delta x = \frac{2 - 0}{4} = 0.5\).
Identify the left endpoints of each subinterval. These will be \(x_0 = 0\), \(x_1 = 0.5\), \(x_2 = 1.0\), and \(x_3 = 1.5\). Note that the left Riemann sum uses the function values at these points.
Evaluate the function \(f(x) = x^2 + 2\) at each left endpoint: calculate \(f(x_0)\), \(f(x_1)\), \(f(x_2)\), and \(f(x_3)\).
Multiply each function value by the width \(\Delta x\) to find the area of each rectangle: \(f(x_i) \times \Delta x\) for \(i = 0, 1, 2, 3\).
Sum all these rectangle areas to approximate the total area under the curve on [0, 2]: \(\text{Left Riemann Sum} = \sum_{i=0}^{3} f(x_i) \Delta x\). This sum represents the approximate area bounded by the graph and the x-axis.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
4m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Riemann Sums

Riemann sums approximate the area under a curve by dividing the interval into subintervals and summing the areas of rectangles formed using function values at specific points. The left Riemann sum uses the left endpoint of each subinterval to determine the rectangle height, providing an estimate of the integral.
추천 영상:
가이드 코스
06:11
Introduction to Riemann Sums

Partitioning the Interval

Partitioning involves dividing the interval [0, 2] into equal subintervals, here n = 4, to create smaller segments for approximation. Each subinterval has length Δx = (b - a)/n, which is essential for calculating the width of rectangles in the Riemann sum.
추천 영상:
08:44
Interval of Convergence

Function Evaluation at Endpoints

To compute the left Riemann sum, evaluate the function f(x) = x² + 2 at the left endpoints of each subinterval. These values determine the heights of the rectangles, which when multiplied by the subinterval width and summed, approximate the total area under the curve.
추천 영상:
가이드 코스
4:26
Evaluating Composed Functions