WASHINGTON (AP) -- The Federal Reserve on Monday approved big online broker Charles Schwab Corp.'s purchase of old-line investment firm U.S. Trust Corp., the financial industry's first major melding of old and new in the 21st century. The vote was 5-0 by the central bank's board of governors, who determined that the acquisition of U.S. Trust by the nation's largest discount and online brokerage would not threaten competition.