# Vector tangent to axis?

1. Nov 14, 2013

### cxcxcx0505

How does it look like if three unit vectors at a point such that each vector is tangent to one of the axes in 3-Dimensional Cartesian System? Can anyone illustrate about this? Thanks.

2. Nov 14, 2013

### phinds

It looks exactly like the standard drawing of a 3D graph basis, just with the center offset accordingly (unless your point is AT the origin, in which case it is exactly the standard drawing)

3. Nov 14, 2013

### cxcxcx0505

Does it mean that the vector is parallel to the axis?

4. Nov 14, 2013

### Staff: Mentor

Which vector and which axis?

You mentioned three unit vectors and three axes in your OP.

5. Nov 14, 2013

### cxcxcx0505

each unit vector parallel to each axes? if I have three unit vector u, v ,w, and axes x , y, z , then u parallel to x , v parallel to y , w parallel to z?

6. Nov 14, 2013

### Staff: Mentor

If each one is tangent to an axis, then it is parallel to that axis.

7. Nov 15, 2013

### cxcxcx0505

I'm reading "An Introduction to Tensors for Students of Physics and Engineering"

I cannot understand in the triangular coordinate systems, how i and i* now meet at an angle of 60°?