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2 -2 4 -4 2 -2 4 -4 6 -6 The equation y = x2 is graphed above. Quadratic equations (equations with 2 as the highest power) are curved. The curve is called a Parabola. Click OK Linear Equation (Line Graph) ? ◡ Quadratic Equation (Parabola graph) ? 2 -2 4 -4 2 -2 4 -4 6 -6 Equation of the graph y =x2 Axis of symmetry Vertex Other points on the parabola Click OK 2 -2 4 -4 2 -2 4 -4 6 -6 Equation of the graph ? y =x2 Axis of symmetry ? Vertex ? Other points on the parabola ? 2 -2 4 -4 2 -2 4 -4 6 -6 A B D E C Which arrow (A, B, C, D, or E) shows the axis of symmetry? 2 -2 4 -4 2 -2 4 -4 6 -6 Axis of symmetry x = -2 ( , ) What are the (x,y) coordinates of the vertex? The VERTEX (turning point) of the graph is always on the axis of symmetry. 2 -2 4 -4 2 -2 4 -4 6 -6 Axis of symmetry ? Vertex ? Step 1: Find the Axis of symmetry Step 2: Find vertex on the axis of symmetry ( -2, -1 ) 2 -2 4 -4 2 -2 4 -4 6 -6 Axis of symmetry x = -2 ■ ▲ Vertex Step 3: Plug x values into the equation of the parabola, y = x2 + 4x + 3 to plot other points on the parabola. ( -2, -1 ) Click OK 2 -2 4 -4 2 -2 4 -4 6 -6 Axis of symmetry x = -2 ▲ ? ■ ? ■ ▲ Vertex Step 4: Reflect (fold) the other points over the axis of symmetry. Drag the reflected points to the correct location ( -2, -1 ) 2 -2 4 -4 2 -2 4 -4 6 -6 Axis of symmetry x = -2 ? ▲ ■ ■ ▲ Vertex ( -2, -1 ) ? (Do you know the axis of symmetry equation from vertex coordinates?) You have plotted 5 points on the parabola Step 2 Step 1 Step 3 Step 4 ◡ ◡ Use the axis of symmetry to find the VERTEX ? Find the AXIS OF SYMMETRY (SUCH AS X = 3) ? Plot 2 other points by plugging new x values in the original equation (such as y = x2 + 8x - 20) ? Reflect the 2 points over the axis of symmetry for a total of 5 points (including the vertex) ? ◡ Graphing Parabolas ◡ ◡ ◡ ◡ ◡ ◡ ◡ ◡ The End ◡ ● ◒ |