integration tutorial: analysis

Consider the integral
int 01 6p2 - p + 4 dp
This is a definite integral, so we need to find the area under the integrand f(p), which we do by using the Fundamental Theorem of Calculus: we find an antiderivative, evaluate it at the endpoints of the integral, and take the difference of the values.
To find an antiderivative of f(p), we go through our list of integration methods:
  1. Recognize elementary antiderivatives
  2. Rewrite the integrand to make it easier
  3. Use substitution to reverse the chain rule or simplify the integrand
  4. Use integration by parts
  5. Use inspection to see the value of a definite integral
to find one that works for this integrand. In this case, only one method is appropriate. We use basic antidifferentiation to determine the antiderivative. This is shown below.
Basic antidifferentiation:
In this case, by using rules for basic antiderivatives we can just write down the antiderivative of the integrand:
int 6p2 - p + 4 dp = 2p3 - (1/2)p2 + 4p + C
To evaluate the definite integral, we take this antiderivative, evaluate it at the endpoints of the integral (0 and 1), and take the difference of the values. This gives
[ 2(1)3 - (1/2)(1)2 + 4(1) ] - [ 2(0)3 - (1/2)(0)2 + 4(0) ] = 11/2.
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integration analysis
Last Modified: Wed Feb 6 13:53:59 EST 2002
Comments to glarose@umich.edu
©2002 Gavin LaRose, UM Math Dept.