Domain and Range


Looking back at the Investigation, did you notice anything about the effect of \(a\) and \(q\) on the domain and range? The domain for all the functions was the same, {\(x | x \in \rm{R}\)}, but the range changed depending upon the values of \(a\) and \(q\).




 Key Lesson Marker

Domain and Range


For quadratic functions of the form \(f(x) = a(x - p)^2 + q \):

The domain is {\(x | x \in \rm{R}\)}.

If \(a > 0 \), then the range is {\(y | y \ge q, \thinspace y \in \rm{R}\)}.

If \(a < 0 \), then the range is {\(y | y \le q, \thinspace y \in \rm{R}\)}.