411 REFERENCE · Wikibooks
HSC Extension 1 and 2 Mathematics/Integration
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Area
Fundamental Theorem of Calculus: , where
Area between two curves
Volume of solids of revolution
Recall that the volume of a solid can be found by
where is the cross-sectional area and is the depth of the solid, which is perpendicular to the cross-sectional area.
Similarly, the volume of solids with circular cross sections can be calculated by
rotating a curve about an axis (generally or axis)
integrating to sum the areas of the slices of circles
Since the area of a circle is , then the integral to evaluate the volume of a solid generated by revolving it around the -axis is
Notice this is a sum of areas of the "slices" of circular cross sections of the solid, i.e. .
Approximate integration
Trapezoidal rule
One interval (2 function values):
-intervals ( function values):
Simpson's rule