Cautious optimism over corporate earnings sent stocks higher. Companies start reporting their second-quarter results this week. Analysts predict earnings growth for S&P 500 companies of 3%, on average, down from 5% in the first quarter but with profits still at record levels. Dell was a big gainer; an advisory firm backed a plan to take the computer company private. Founder Michael Dell and Silver Lake Partners are offering $24.4 billion, or $13.65 a share. The Russell 2000 index closed at a record high; the Nasdaq had the smallest gain, weighed down by Intel’s slump as an analyst warned of waning demand for smartphones. Other chip makers fell, too.