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Ch. 5 - Integration
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 5, Problem 5.1.9

Approximating area from a graph Approximate the area of the region bounded by the graph (see figure) and the 𝓍-axis by dividing the interval [1, 7] into n = 6 subintervals. Use a left and right Riemann sum to obtain two different approximations.                                                                                                                                                                         
fig

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First, determine the width of each subinterval by dividing the total interval length by the number of subintervals: \(\Delta x = \frac{7 - 1}{6} = 1\).
Identify the left endpoints of each subinterval for the left Riemann sum: these are \(x = 1, 2, 3, 4, 5, 6\). For each of these points, find the corresponding function values \(f(x)\) from the graph.
Calculate the left Riemann sum by multiplying each function value at the left endpoints by the width \(\Delta x\) and summing them up: \(L = \sum_{i=0}^{5} f(x_i) \Delta x\) where \(x_i\) are the left endpoints.
Identify the right endpoints of each subinterval for the right Riemann sum: these are \(x = 2, 3, 4, 5, 6, 7\). For each of these points, find the corresponding function values \(f(x)\) from the graph.
Calculate the right Riemann sum by multiplying each function value at the right endpoints by the width \(\Delta x\) and summing them up: \(R = \sum_{i=1}^{6} f(x_i) \Delta x\) where \(x_i\) are the right endpoints.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Riemann Sums

Riemann sums approximate the area under a curve by dividing the interval into subintervals and summing the areas of rectangles. The height of each rectangle is determined by the function value at specific points, such as the left or right endpoints of each subinterval.
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Introduction to Riemann Sums

Left and Right Endpoint Approximations

Left and right Riemann sums use the function values at the left or right endpoints of each subinterval to determine rectangle heights. Left sums may underestimate or overestimate the area depending on the function's behavior, while right sums provide a complementary approximation.
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Left, Right, & Midpoint Riemann Sums

Partitioning the Interval

Dividing the interval [1, 7] into n = 6 equal subintervals means each subinterval has width Ξ”x = (7-1)/6 = 1. This partitioning is essential for calculating the Riemann sums, as it defines the base of each rectangle used in the approximation.
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Related Practice
Textbook Question

Indefinite integrals Use a change of variables or Table 5.6 to evaluate the following indefinite integrals. Check your work by differentiating.                                                                                  

                                                                                                                                                                    

 βˆ« sec 4w tan 4w dw

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βˆ«Β²β‚‹β‚‚ [(xΒ³ ― 4x) / (xΒ² + 1)] dx 

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 βˆ«β‚‹β‚Β² ( ―|𝓍| ) d𝓍

Textbook Question

Use the given substitution to evaluate the following indefinite integrals. Check your answer by differentiating.                                                                                              

                                                                                                                                                                                       

 βˆ« 8𝓍 cos (4𝓍² + 3) d𝓍, u = 4𝓍² + 3

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Textbook Question

Symmetry in integrals Use symmetry to evaluate the following integrals.

βˆ«Β²β°β°β‚‹β‚‚β‚€β‚€ 2x⁡ dx

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Definite integrals Evaluate the following integrals using the Fundamental Theorem of Calculus


βˆ«ΒΉβ‚/β‚‚ (t⁻³ ― 8) dt

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