10-1 Exploring Quadratic Graphs(with calculator)

Warm-up

1) What is the cost of 95 min with company B?

2) What is the cost of 132 min with company A?

3) What is the cost of 178 min with company C?

Company Monthly Cost for 100 Min

Monthly Cost for over 100 Min

A 25.00 0.05

B 21.00 0.07

C 19.00 0.09

Notes

Parabola y = ax2 + bx + c

Axis of Symmetry – fold or line that divides parabola into 2 matching halves

Vertex – highest or lowest point of a parabolaIf a>0, then parabola opens up (minimum)

If a<0, then parabola opens down (maximum)

Parabola

Examples: Activity 24Function Sketch Value of a Open up

or downVertex highest or lowest

Axis of symmetry

Same, Narrow or Wide

Y = x2 1 up lowest X=0 sameY = -1x2

Y = 6x2

Y = -6x2

Y=0.3x2

Y=-0.3x

Notes

What does “a” do to the graph?

Examples: Activity 25Function Sketch Value of c Coordinates

of VertexAxis of Symmetry

Y = 1x2 + 0

Y = 1x2 + 2

Y = 1x2 – 4

Y = 1x2 – 8.5

Notes

What does “c” do to the graph?

Examples: Activity 26

Function Sketch Value of b

Coordinates of Vertex

Axis of Symmetry

Y = x2 + 12

Y = x2 – 4x + 12

Y = x2 + 11x + 12

Y = x2 – 8.8x + 12

Notes

What does “b” do to the graph?