WASHINGTON (AP) — Lots of apps claim they can help you fight jet lag. [...] Michigan researchers say mathematical formulas suggest it's possible to adjust to new time zones a bit faster than previously thought, and they created their own free app to help. "If you get light in the wrong time or wrong way, it'll send you the wrong direction," said University of Michigan math professor Daniel Forger, who led the research published Thursday. In a study partly funded by the Air Force, the Michigan team used two equations proven to predict someone's circadian rhythm, and with computer modeling calculated different schedules of light exposure for more than 1,000 possible trips.