What is the cross product of any vector with itself (e.g., mathbfutimesmathbfu\\mathbf{u} \\times \\mathbf{u}mathbfutimesmathbfu)?
1
∣u∣2|u|^2∣u∣2
mathbfu\\mathbf{u}mathbfu
mathbf0\\mathbf{0}mathbf0