Apple's tablet computing device, once a red-hot consumer gadget, has suffered from a steady decline in sales over the last year. [...] Cook said he sees a future for the iPad in business settings, where workers can use specialized iPad apps created by IBM and other commercial software developers. At a time when market researchers say the personal computer market is shrinking, Apple is actually increasing its sales of Macs. [...] the Mac contributed $5.6 billion of Apple's revenue last quarter and saw unit sales grow 10 percent, while market researchers at International Data Corp.