1. Definition
A 3D vector has magnitude √(x²+y²+z²) and dot product x₁x₂+y₁y₂+z₁z₂, with cosθ=(a·b)/(|a||b|).
3. Properties & Laws
- Magnitude √(x²+y²+z²);
- Dot = sum of products;
- a⊥b iff dot=0;
- Same laws as 2D.
4. Steps
- Enter the two vectors;
- Click "Calculate";
- Or click "Load Example".
5. Worked Examples
Example: (1,2,2),(2,1,2): magnitudes 3, dot 8, cos 8/9.
6. Common Pitfalls
Include z;
Sum three squares;
Zero has no angle.