• Slides: 10

• The value of the coefficient a determines the direction the parabola faces. • When a is positive, the parabola faces up. • When a is negative, the parabola faces down. Table of Contents

• The vertex of a parabola is the lowest point (minimum y-value) on the graph of a parabola … … or the highest point (maximum y-value) on the graph. Maximum Vertex Minimum Table of Contents

• The axis of symmetry of a parabola is the vertical line going through the vertex. • Example 2 Draw the axis through the vertex. Notice the symmetry of the two branches of the parabola about the axis. Table of Contents

• The equation of the axis of symmetry is given by In this case, the equation of the axis of symmetry is given by: Table of Contents

• When graphing quadratic functions, it can be helpful to plot all intercepts. x-intercepts y-intercepts Set y = f (x) = 0 and solve for x. Set x = 0 and solve for y. This is where the graph intersects the x-axis. This is where the graph intersects the y-axis. Table of Contents