CALCULUS Understanding Its Concepts and Methods

Double and triple integrals, Fubini's theorem, Iterated integral

Suppose
*f*(*x*,*y*)
is a continuous function on the rectangle
*R* = [*a*,*b*]
**x** [*c*,*d*].
If
*f*(*x*,*y*)
> 0
on the rectangle
*R*,
then the double integral of
*f* over
*R*
is the volume of the solid above
*R*
and below the surface
*z = f*(*x*,*y*).

If *f*(*x*,*y*)
also takes on negative values, then the double integral is the difference
between the volume where
*f*
is positive and the volume where
*f*
is negative.

The double integral of a function on a rectangle can be computed by an iterated integral:

Fubini's
theoremIf
is continuous on
*R* = [*a*,*b*]
**x** [*c*,*d*],
thenThe
integrals on the right above are iterated
integrals.

We can write the triple integral over a rectangular solid
*E*
as the limit of a sum. To do this, subdivide
*E*
into small rectangular solids
*S _{i}*
of volume

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Double integrals in polar coordinates

Triple integrals in cylindrical coordinates

Triple integrals in spherical coordinates

Copyright © 2006 Darel Hardy, Fred Richman, Carol Walker, Robert Wisner. All rights reserved. Except upon the express prior permission in writing, from the authors, no part of this work may be reproduced, transcribed, stored electronically, or transmitted in any form by any method.