# Homework Help: Graphing calculator help

1. Sep 23, 2009

### Bachelier

I am trying to graph: r²= sinθ in Polar mode.

2. Sep 23, 2009

### DMOC

Did you change your calculator to use Polar GC and not Rect GC (assuming you're using a TI-83 or 84).

3. Sep 23, 2009

### Bachelier

Yes, I did. I know how to graph polar curves, but the issue I am having is with r square.
The calculator can only graph r !!!

4. Sep 23, 2009

### Office_Shredder

Staff Emeritus
Graph

$$r= \sqrt{sin \theta }}$$

instead. r is always positive anyway so you shouldn't miss anything

5. Sep 23, 2009

### Bachelier

it only graphs half the lemniscate on 0, 2pi

the only way I could find to draw it is using r= square root theta and - square root theta simultaneousely.

6. Sep 23, 2009

### Office_Shredder

Staff Emeritus
It should only graph half. If theta is between pi and 2pi, sin(theta) is negative and no value of r will square to a negative number.

EDIT: Unless you allow negative r for a value of theta between pi and 2pi. In which case there's probably no way to graph this on your graphing calculator with a single equation

7. Sep 24, 2009

### Bachelier

yeah, I missed that.

But how can we draw a lemniscate then?