#### You may also like ### Sine Problem

In this 'mesh' of sine graphs, one of the graphs is the graph of the sine function. Find the equations of the other graphs to reproduce the pattern. ### Parabolic Patterns

The illustration shows the graphs of fifteen functions. Two of them have equations y=x^2 and y=-(x-4)^2. Find the equations of all the other graphs. ### More Parabolic Patterns

The illustration shows the graphs of twelve functions. Three of them have equations y=x^2, x=y^2 and x=-y^2+2. Find the equations of all the other graphs.

# Cubic Spin

##### Age 16 to 18 Challenge Level:

If the graph of the cubic polynomial has rotational symmetry then a maximum point must be rotated to become a minimum and vice versa so the center of rotation will be the midpoint of the line joining the maximum and minimum points. If there are no maximum and minimum points then consider the point of inflexion.

The graph of a function has rotational symmetry about the origin if and only if $f(-x) = -f(x)$. You can do this question without calculus if you can find the transformation of coordinates that removes the quadratic term from the polynomial equation.