US economic growth was less sluggish than previously thought in the second quarter as exports grew more than imports and businesses raised their investments, hopeful signs for the economic outlook. Gross domestic product expanded at a 1.4 percent annual rate, the Commerce Department said on Thursday in its third estimate of GDP. That was up from the 1.1 percent rate it reported last month and higher than analysts’ expectations. The revision incorporated data that showed businesses cut investments in buildings and equipment less than the government previously estimated, while they sank more money into research and development. Other data released by the Commerce Department showed America’s trade deficit for goods shrank in August, boding well for third-quarter growth. “It now appears that growth is slowly making its way back on to firmer ground,” said Michael Feroli, an economist at JPMorgan in New York.