Save guides, add subjects and pick up where you left off with your BBC account. All quadratic functions have the same type of curved graphs with a line of symmetry. The graph of the quadratic ...

David Alan Grier, “Irene Stegun, the Handbook of Mathematical Functions, and the Lingering Influence of the New Deal,” American Mathematical Monthly, 113 #7, August-September 2006, pp. 585-597.