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Area Between Two Curves. 7.1. Area Formula. If f and g are continuous functions on the interval [a, b], and if f(x) > g(x) for all x in [a, b], then the area of the region bounded above by y = f(x), below by y = g(x), on the left by x = a and on the right by x = b is…. .
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Area Formula • If f and g are continuous functions on the interval [a, b], and if f(x) > g(x) for all x in [a, b], then the area of the region bounded above by y = f(x), below by y = g(x), on the left by x = a and on the right by x = b is….
Example 1 • Find the area of the region bounded above by y = x + 6 and below by y = x², and bounded on the sides by the lines x = 0 and x = 2.
It’s possible for the upper and lower boundaries to intersect at a point on the left and/or right sides. If this happens we will have to determine the points of intersection to obtain the limits of our integration.
Example 2 • Find the area of the region that is enclosed between the curves y = x² and y = x + 6
It’s possible for the upper and lower boundary to consist of two or more curves, in which case we can subdivide the region into smaller pieces to find the area
Example 3 • Find the area of the region that is enclosed between the curves x = y² and y = x – 2 • What’s different about this question?
Two ways to solve….. #1 • Subdivide the regions • Equation of top graph – equation of bottom graph • Equations must be solved in terms of y and bound are determined by x values
#2 • Reverse the roles of x and y • When reversing roles you always subtract the graph on the right – graph on left • Must solve equations in terms of x and gets bounds in terms of y
Practice • Sketch the region enclosed by and then find the area.
Practice • Pg. 448 (1 – 23 odd)