Apple Inc. posted first-quarter profit that disappointed investors and gave a forecast that fell short of analysts' estimates, sending the shares down 11 percent and signaling an economic slowdown may curb demand. Net income rose 57 percent to $1.58 billion, or $1.76 a share, from $1 billion, or $1.14, a year earlier, Apple said today in a statement. Sales gained 35 percent to $9.61 billion. Apple fell $17.38 to $138.26 in extended trading. The stock dropped $5.72, or 3.5 percent, to $155.64 at 4 p.m. New York time in Nasdaq Stock Market trading. The shares have declined 23 percent since reaching a record $202.96 in December. Also, Motorola Inc said Wednesday it expects first-quarter sales of its mobile handsets to decline "significantly" from the fourth quarter, contributing to an expected loss. Motorola said its decline will be steeper than typical seasonal fluctuations in first-quarter handset sales. The company blamed that in part on slowing demand for some of its products, including newly introduced phones. Motorola also said it expects to lose market share in the first quarter The news presents a harbinger of a day of further losses on Wall Street, as investors are still not confident that the Federal Reserve can stop the destruction wrought by the sub-prime mortgage crisis and ensuing credit crunch. Less than two hours before the start of trading, Dow Jones Industrial Average futures dropped 136 points to 11815.