problem Favourite 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.
problem Favourite Squareness Age 16 to 18 Challenge level The family of graphs of x^n + y^n =1 (for even n) includes the circle. Why do the graphs look more and more square as n increases?
problem Implicitly Age 16 to 18 Challenge level Can you find the maximum value of the curve defined by this expression?