Thomas A. Moore -- August 2007
This program evaluates the probability that a molecule will have a speed within a given range, using the form of the integral given in equation T7.12a, except with arbitrary lower and upper limits x1 and x2 respectively, where x = v/vP and vP is the the most probable molecular speed defined by equation T7.4b. Enter values for x1 and x2, and press the "Evaluate" button to display the fractional probability that the molecule has a speed within the range in question. (You may type "inf" or "infinity" in the top box to specify an upper limit of infinity.) The program evaluates the integral by dividing up the interval between x1 and x2 into 1000 equal steps and using the Midpoint Rule (i.e. the area under the curve is approximated by the total area of a set of 1000 vertical bars whose combined widths spans the integration range and where each bar's height is the integrand's value at the midpoint of that bar's width.)
I have tried to make this program as transparent and as easy-to-use as possible. Please send any bug reports or feature requests to me at email@example.com. This program was written using REALBasic, a superb development environment for Macintosh, Windows, and Linux platforms. For more information, visit www.realbasic.com. This program is freeware, and may be freely distributed, used, and/or modified, subject to the terms of the GNU General Public License, version 2 or higher (http://www.opensource.org/licenses/gpl-license.php).