to txuser: As far as I can tell, for Bahamas one neeeds a tourist visa. For Mexico - as long as the cruise is not more than 3 days, one does not need any visa (anyone in the world does not need a Mexico visa for a cruise upto 3 days). For entering back in US, either you can enter on a stamped visa or on AP. Pls check as well.
Discriminant of a Quadratic. The number D = b2 â 4ac determined from the coefficients of the equation ax2 + bx + c = 0. The discriminant reveals what type of roots the equation has. Note: b2 â 4ac comes from the quadratic formula.
1. Divide the amount of the substance at one point in time by the amount remaining after a period of time. 1  The formula for calculating half life is as follows: t1/2 = t * ln(2)/ln(N0/Nt). 2  In this formula, t = time gone by, N 0 = amount of substance at the beginning, and N t = amount of substance after a period of time.