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 tells us there are two roots when positive, one root when zero, and no roots when negative. b^2-4ac = (-8)^2-4*3*1 = 52 is positive, so there are two roots. The discriminant is just part of the quadratic equation. The quadratic equation gives us the exact real number roots of any equation in the form ax^2+bx+c=0. The quadratic equation is x = (-b \pm sqrt(b^2-4ac))/(2a), where \pm means that we have two values, one using + (addition) and one using - (subtraction). Let D = b^2-4ac.