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Ch. 6 - Applications of Integration
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 6, Problem 6.2.51

Find the area of the region described in the following exercises.


The region bounded by y=e^x, y=2e^−x+1, and x=0

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Step 1: Identify the boundaries of the region. The region is bounded by the curves y = e^x, y = 2e^(-x) + 1, and the vertical line x = 0. This means the region lies between these curves and starts at x = 0.
Step 2: Determine the points of intersection between the curves y = e^x and y = 2e^(-x) + 1. To find these points, set e^x = 2e^(-x) + 1 and solve for x. This will give the x-values where the two curves meet.
Step 3: Set up the integral to calculate the area. The area is found by integrating the difference between the upper curve (y = 2e^(-x) + 1) and the lower curve (y = e^x) over the interval determined by the points of intersection and x = 0.
Step 4: Write the integral expression for the area. The area can be expressed as: ∫[x=0 to x=intersection] [(2e^(-x) + 1) - e^x] dx. This represents the vertical distance between the curves integrated over the specified interval.
Step 5: Evaluate the integral. Break the integral into simpler parts if necessary, such as ∫[x=0 to x=intersection] 2e^(-x) dx, ∫[x=0 to x=intersection] 1 dx, and ∫[x=0 to x=intersection] e^x dx. Compute each part and combine the results to find the total area.

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Key Concepts

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

Definite Integrals

Definite integrals are used to calculate the area under a curve between two points on the x-axis. In this context, the area between the curves y=e^x and y=2e^−x+1 can be found by integrating the difference of these functions over the appropriate interval. The limits of integration will be determined by the points where the curves intersect.
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Curve Intersection

Finding the intersection points of the curves y=e^x and y=2e^−x+1 is essential for determining the limits of integration. This involves setting the two equations equal to each other and solving for x. The x-values at which the curves intersect will define the boundaries of the area to be calculated.
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Exponential Functions

Exponential functions, such as y=e^x and y=2e^−x+1, are characterized by their rapid growth or decay. Understanding their behavior is crucial for analyzing the region they enclose. The function e^x increases without bound as x increases, while 2e^−x+1 approaches 1 as x increases, creating a bounded area between them.
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