Calculus in the palm of your hand.

Calculus in the palm of your hand

Most banquets celebrating an important anniversary feature a prominent guest speaker. But when more than 1,700 mathematicians gathered in Atlanta to kick off a year-long celebration marking the centennial of the American Mathematical Society, the center of attention was a machine: an advanced scientific calculator with many of the mathematical capabilities of a computer. Nearly every mathematician present had exercised the option of purchasing along with a banquet ticket the brandnew HP-28S at a bargain price.

The delivery on Jan. 7 of 1,500 calculators, the first units of the HP-28S to come off the Hewlett-Packard assembly line in Corvallis, Ore., marked the dramatic debut of a calculating machine capable of handling not just numbers and simple operations such as multiplication but also algebraic expressions and complex tasks such as taking derivatives and plotting graphs. For example, with this compact, hand-held machine, a user can do the kinds of problems featured in beginning calculus textbooks (SN: 11/14/87, p. 317). Entering the algebraic expression "sin x," then pressing a few keys to take its derivative, displays the answer "cos x" on the calculator's four-line liquid crystal display. A few more keystrokes generate a graph of the equation.

The HP-28S and its predecessor, the HP-28C introduced last year, are the most sophisticated hand-held calculators yet produced, says mathematician John W. Kenelly of Clemson (S.C.) University. Although a few calculators can now plot graphs if coordinates of points on a curve are supplied, no others can manipulate symbols and algebraic expressions. Kenelly has been teaching an introductory calculus course in which every student uses an HP-28C regularly. The HP-28S is even faster than the original and has a larger memory that allows it to do bigger problems, especially those involving series and matrices.

"What this machine does has been available on computers for quite a while," says Kenelly. "The convenience of it is the real breakthrough. I have had a very rich year with the 28C because it's been with me on airplanes, and the airline industry has made it very easy for me to find plenty of time to play with it."

The intense curiosity and sense of novelty with which many mathematicians at the banquet greeted the new calculator seemed a little worrisome to at least one mathematician who observed the proceedings. It showed, he said, how novel the idea of using a computer or a sophisticated calculator to assist in teaching college mathematics courses or in conducting mathematical research still is to many mathematicians.