parabola: set of all points in a plane that are the same distance from a fixed line & a fixed...

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10.2 PARABOLAS

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Page 1: Parabola: set of all points in a plane that are the same distance from a fixed line & a fixed point not on the line  Focus: that fixed point; lies

10.2 PARABOLAS

Page 2: Parabola: set of all points in a plane that are the same distance from a fixed line & a fixed point not on the line  Focus: that fixed point; lies

Definitions

Parabola: set of all points in a plane that are the same distance from a fixed line & a fixed point not on the line

Focus: that fixed point; lies on the axis of symmetry

Directix: that fixed line; perpendicular to the axis of symmetry

Vertex: lies halfway between the focus & directix

Page 3: Parabola: set of all points in a plane that are the same distance from a fixed line & a fixed point not on the line  Focus: that fixed point; lies

Recall

In chapter 5, all parabolas opened up or down with a vertical axis of symmetry

Look at bottom of page 595 togeter

Page 4: Parabola: set of all points in a plane that are the same distance from a fixed line & a fixed point not on the line  Focus: that fixed point; lies

Standard Equation of Parabola with vertex at origin

Equation Focus Directix Axis of Sym.

Opens

Vertical Up or Down

Horiz. Left or Right

2 4x py

2 4y px

y p 0, p

,0p x p

0x

0y

Page 5: Parabola: set of all points in a plane that are the same distance from a fixed line & a fixed point not on the line  Focus: that fixed point; lies

Examples

Identify the focus & directix of the parabola given by . Draw the parabola

Write the equation of the parabola show

HW: p598-599 #16-37all, 38-76even

23

4x y