Quadratic functions are among the most familiar in mathematics. The general form of a quadratic function is y = ax² + bx + c, where a, b, and c are real valued constants, except that a cannot be 0. The graph of a quadratic function is called a parabola, which looks like a "U" with the sides bent outwards. When a is positive, the parabola opens upward, looking somewhat like a smile; when a is negative, the parabola opens downward like a frown. The absolute value of a determines how quickly the parabola rises or falls; the larger the absolute value of a, the more rapidly the parabola rises or falls. The values of b and c in the quadratic equation determine the location of the parabola in the xy-plane. In particular, if b = 0, then the parabola will be symmetric to the y-axis; its highest(or lowest) point, called the...