Parabolas

Summary

quadratic functions have graphs that are parabolas.

the general equation of a quadratic function can be given in two forms:

y = ax 2 + bx + c or y = a(x − h) 2 + k

in both forms the highest exponent of x is 2.

the vertex, stationary point or turning point gives either the maximum or minimum value of the function.

Key Skills

  • sketch parabolas using the factorised form of a quadratic function or by the transformation approach.
  • find the intercepts of a parabola
  • place the axis of symmetry of a parabola
  • find the coordinates of the vertex of a parabola.

Vocabulary

parabolastationary pointturning pointmaximum value, minimum valuevertex
axis of symmetry.