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.
The discriminant refers to a particular section of the quadratic formula, which is #-b +- sqrt(b^2 - 4ac)/(2a)#. The discriminant is only the following part of the formula, the part under the radical/square root sign: #sqrt(b^2 - 4ac)#. In this case, the discriminant would be: #(-4)^2 - 4(1)(10)#. Or just #16 - 40# which is equal to #-24#.