QUADRATIC FUNCTIONS IN STANDARD FORM 4.1B
Review A quadratic function can be written in the form y = ax 2 + bx + c. The graph is a smooth curve called a parabola.
Other vocabulary Vertex Axis of symmetry Maximum or minimum value
Properties of the graph of y = ax 2 + bx + c The x coordinate of the vertex is x = -b/(2a) The y-intercept is (0,c) If a > 0 the graph opens up, if a < 0 the graph opens down The larger the magnitude of a, the narrower the graph
Steps for graphing quadratics in standard form Find the coordinates of the vertex Decide whether the graph opens up or down Find the y-intercept Reflect that point over the axis of symmetry Graph one other set of points
Practice Graph y = 2x 2 – 8x + 6 Graph y = 3x 2 + 6x + 1 Graph y = -x 2 – 4x + 2 Graph y = 1/3x 2 + 6x – 2 Graph y = x 2 + 4x