In 1972 Hewlett-Packard, Palo Alto, California, introduced the HP-35, their first pocket calculator, and the first pocket scientific calculator with trigonometric and exponential functions. The unit, which fit in a shirt pocket, was priced $395.
"Before the HP-35, the only practical portable devices for performing trigonometric and exponential functions were slide rules. Existing pocket calculators at the time were only four-function, i.e., they could only do addition, subtraction, multiplication, and division. It had been originally known simply as 'The Calculator', but Hewlett suggested that it be called the HP-35 because it had 35 keys" (Wikipedia article on HP-35, accessed 03-10-2012).