# Homework Help: Geometry (great circles)

1. Nov 27, 2005

### Pearce_09

consider the 3 great circles C1,C2,C3 with respective normals
(0,-1,1) (1,0,1) (1,1,0), and let f = Rc3Rc2Rc1

is f orientation preserving or orientation reversing.

can i make a matrix using the normals... then calculate the determinate of A. and if its negative then its reversing and if its positive then its preserving... or can i only calculate the matrix when its givin to me....

2. Nov 28, 2005

### HallsofIvy

I don't understand your notation. What does "Rc3Rc2Rc1" mean? I assume that the c3, c2, c1 should really be C3, C2, C1, but what is R?

3. Nov 28, 2005

### Pearce_09

R means reflection, sorry i should have stated that
so reflection in C3 Reflection in C2 and Reflection in C1

4. Nov 28, 2005

### HallsofIvy

"Reflection in C3"? C1, C2, C3 are great circles on a sphere? And reflection is to the other hemisphere?
Reflection, generally, is orientation reversing. Two reflections would be orientation preserving and 3, as you have here, orientation reversing.