Theorem (Boole's
Rule) Consider
over
,
where
,
,
,
and
. Boole's
rule is
.
This is an numerical approximation to the integral of
over
and we have the expression
.
The remainder term for Boole's rule is , where
lies somewhere between
,
and have the equality
.
Composite Boole's
Rule
Our next method of finding the area under a
curve
is by approximating that curve with a series of
quartic segments that lie above the intervals . When
several parabolas are used, we call it the
composite Boole's rule.
Theorem (Composite
Boole's Rule) Consider
over
. Suppose
that the interval
is subdivided into
subintervals of
equal width by
using the equally spaced sample points for . The
composite Boole's rule for
subintervals is
.
This is an numerical approximation to the integral of
over
and we write
.
Remainder term for
the Composite Boole's Rule
Corollary (Boole's
Rule: Remainder term) Suppose that
is subdivided into
subintervals of
width . The
composite Boole's rule
.
is an numerical approximation to the integral, and
.
Furthermore, if
, then
there exists a value
with so
that the error term has
the form
.
This is expressed using the "big
"
notation .
Remark. When the step size is reduced by
a factor of
the remainder term
should be reduced by approximately
.
Algorithm Composite Boole's Rule. To
approximate the integral
,
by sampling at
the equally
spaced sample points
for , where . Notice
that and .
Mathematica Subroutine (Boole's Rule).
Object oriented programming.
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