Quadratic functions notes

This document contains notes for quadratic functions. They should be very useful when working with quadratic functions.

• The general form of a quadratic equation is y=ax² + bx + c where a, b, c are constants and a ≠ 0.
• Quadratic equations can be solved by:
  • Factorisation
  • Completing the square.
    

  • Using the formula
    
• A quadratic equation has two solutions, which may be equal.
  To sketch a quadratic graph:
  • decide on the shape
    
• work out the x-axis and y-axis crossing points
• check the general shape by considering the duscriminant b² – 4ac