problem Witch of Agnesi Age 16 to 18 Challenge level Sketch the members of the family of graphs given by y = a^3/(x^2+a^2) for a=1, 2 and 3.
problem Folium of Descartes Age 16 to 18 Challenge level Investigate the family of graphs given by the equation x^3+y^3=3axy for different values of the constant a.