Quadratic with Variable y-intercept

Varying the constant c in a quadratic in the form y = a x² + b x + c results in the VERTICAL movement of the quadratic. The SHAPE of the quadratic stays the same. The y-intercept is marked by a red square. In this animation ONLY the y-intercept is being changed. The coefficients "a" and "b" are to the right of the equation. Change these and rerun the animation to study the effect of these coefficients on the equation.

Note that when the quadratic's vertex is on the x-axis there is only one root at the vertex location. Later on in mathematics we will refer to this position as being that of a "perfect square."

Also note that the x-intercepts (blue squares), also called roots, disappear when the quadratic no longer crosses the x-axis (is above the x-axis in this case). Later on in mathematics we will learn that the roots have become "imaginary."

Developed by Dana Lee Ling with the support and funding of a U.S. Department of Education Title III grant and the support of the College of Micronesia - FSM. Notebook material ©1999 College of Micronesia - FSM. For further information on this site, contact dleeling@comfsm.fm. Designed and run on a Gateway GP6-350 with 64 MB RAM, Windows 98 OS using MathView 2.5, Microsoft FrontPage 98, and Microsoft Internet Explorer 5.0.  All equipment and software purchased through a U.S. Dept. of Education Title III grant.