8.2.2 – graphing polar points, converting equations

8.2.2 – Graphing Polar Points, Converting Equations

• To graph polar coordinates, we will do it as a combination of:– 1) Graphing cartesian coordinates– 2) Using the unit circle

The Polar Plane

• A series of circles, with increasing radii • Each radius, for our purposes, is an increase of one unit

• Notice angle measures

The Polar Plane

• To plot on the polar plane• 1) Find the radius, givenby r, in the ordered pair, (r, ϴ)

• 2) Find angle given byϴ, in the ordered pair (r, ϴ)

• Example. Plot the polar point (3, π/2)

• Example. Plot the polar point (1, 4π/3)

• Example. Plot the polar point (2, 3π/4)

Negative Radius

• We really do not have such a thing as a “negative radius” in a real life context– Distance; should be positive

• In the Polar coordinate plane, though, a negative radius may occur

• The radius, -r, is acts as a 180 degree reflection

• Example. Plot the polar point (-1, 11π/6)

• Assignment• Pg. 628• 1-6 all• Plot 13 and 14 which you converted last night

to polar points