1. you have to switch your calculator to polar mode.
2. Enter the equations at r1 and r2 in the y-editor. You'll find the at the -key of your calculator.
3. Use the following window-settings:
min = 0
max = 6.2831... the means it is 2
step = .1308996... that means it is
xmin = -2
xmax = 5
xscl = 1
ymin = -3
ymax = 3
yscl = 1
4. I've attached the drawing.
5. I used a TI84 and I hope that the syntax is the same with a TI85. If not
Remark: Unfortunately the factor 2 is hidden by the cursor in the equation r1