Objectives: • Be able to graph a quadratic function in vertex form • Be able to write a quadratic function in vertex form (2 ways) Vertex Form of a Quadratic Parent Function: Vertex Form of a Quadratic Equation: y x2 f ( x ) a ( x h) 2 k 5 4 3 2 1 -5 -4 -3 -2 -1 1 -1 -2 -3 -4 -5 2 3 4 5 Reflection over x-axis if a is negative, vertical stretch (a > 1) or shrink (a < 1) Vertical Translation Horizontal translation (opposite of what you see!) *The vertex of the parabola is (h, k) and the axis of symmetry is x = h. Graphing Equations in Vertex Form 1 2 Ex 1) y ( x 2) 3 2 a. Vertex (horiz. and vert. translation) 10 8 b. Axis of symmetry 6 c. Table 4 2 -10 -8 -6 -4 -2 2 4 6 8 10 x • Point • Vertex • Corresp. -2 -4 -6 -8 -10 d. Ask: • Correct reflection? • Correct stretch or shrink? y Vertex Form from Graph Ex 4) Write the equation for the following parabola in vertex form: y = a(x – h)2 + k