Parabolic Problems
Another problem I have seen lately is that of parabolas and symmetry, as well as that of intervals, domains, ranges, and other graphical dilemmas. If one is asked to define the interval over which a function is increasing, decreasing, or remaining the same, the answer is always (x 1 , x 2 ). One never uses brackets when referring to an interval! However, if one is asked to define a domain or range, the answer could include one or more brackets: (x 1 , x 2 ], [x 1 , x 2 ), or [x 1 , x 2 ] if referring to the domain; (y 1 , y 2 ], [y 1 , y 2 ), or [y 1 , y 2 ] if referring to the range. (x 1 , x 2 ) and (y 1 , y 2 ) can also be used to describe the domain and range, respectively, in some cases. A function is said to be increasing if the y-values are getting larger, decreasing if they are getting smaller, and constant if they are remaining steady. The domain of the function is the entire group of all the x -values for which the function is continuous, while the range is the entire
