(1) The coordinates of the turning point are found as follows:
- Differentiate, and find the value of for which
- Substitute this value of in the original equation to find the value of
So the turning point is , and it is a minimum since .
(2) The equation of the line of symmetry is simply the line through the turning point parallel to the -axis.
In this example, then, this is .
(3) The -axis intercepts are the values of for which
So the intercepts are and .