Abstract :
Only three short years ago, the HP-35 (featuring Reverse Polish Notation) was introduced and soon won the praise and acceptance of engineers everywhere at an initial $395. But on a strict cost/performance basis, the ¿veteran¿ of portable scientific calculators could be headed toward early retirement. Hewlett-Packard´s latest pocket marvel, the scientific HP-21 at $125, retails $70 below the current price of an HP-35! Not only is the HP-21 cheaper, it also includes a degree/radian switch and handles inverse trig functions, two useful features its older brother lacks. Using fewer batteries and logic chips than any other H-P portable calculator, the HP-21 operates five hours on a full charge.
