Polar Cordinates

In class we learned about polar and rectangular coordinates. 
 
(raduis, theta) is the same as (x,y) when using polar graphs. 


To convert from polar to rectangular you use:
x=rcostheta
y=rsintheta


To convert form rectangular to polar you use: 
r=square root of x^2+y^2
theta=tan^-1 (y/x)

Both of these are on the unit circle.


Example 1


What is (12,5) in polar coordinates?
r^2=√12^2+5^2
r^2=√144+25
r^2=√169
r^2=13


tan(theta)=(5/12)
theta=tan^-1(5/12)
theta=22.6