11-1

This section is all about polar coordinates and plots. In this section I will teach you all how to convert from rectangular coordinates to polar coordinates, convert from polar coordinates to rectangular coordinates, and plot polar coordinates. Rectangular coordinates are in the form of (x, y). Polar coordinates are in the form of (r, theta).

Whenever you convert from polar coordinates to rectangular coordinates, you use these two formulas:
• x = r cos ( theta )
• y = r cos ( theta )

Whenever you convert from rectangular coordinates to polar coordinates, you use these two formulas:
• r = sq. root of ( x^2 + y^2 )
• theta = tan^ -1 ( y/x )

Now I will show you some examples so that you can see how to work a problem that involves polar coordinates.

Example: Convert (5, 0) to polar
• r = sq. root (5^2 + 0^2)
• r = sq. root (25)
• r = +/- 5
• theta = tan^-1 (0/5)
• theta = 0
• (5,0) and (-5,0)


-Braxton