1. Definition
Translate the lines to intersect and take the acute/right angle: cosφ=|u·v|/(|u||v|), the absolute value ensuring an acute angle.
3. Properties & Laws
- cosφ=|u·v|/(|u||v|);
- Range (0°,90°];
- Parallel 0°, perpendicular 90°;
- Any parallel direction works.
4. Steps
- Enter two directions;
- Click "Angle";
- Or click "Load Example".
5. Worked Examples
Example: (1,0,0),(1,1,0): cos=√2/2, φ=45°.
6. Common Pitfalls
Use absolute value;
Zero vectors invalid;
Skew lines do not meet; angle uses translation.