IB DP Maths: AA HL复习笔记2.2.1 Quadratic Functions

What are the key features of quadratic graphs?

The value of a affects the shape of the curve

• • If a is positive the shape is concave up ∪
  • If a is negative the shape is concave down ∩
• The y-intercept is at the point (0, c)
• 
  • These can be found by
    • Factorising
    • Quadratic formula
    • Using your GDC
  • These are also called the x-intercepts
  • There can be 0, 1 or 2 x-intercepts
    • This is determined by the value of the discriminant
  • If a is positive then the vertex is the minimum point
  • If a is negative then the vertex is the maximum point

What are the equations of a quadratic function?

How do I find an equation of a quadratic?