P⃗×Q⃗=0\vec{P} \times \vec{Q}=0P×Q=0
P→⋅Q→=0\overrightarrow{\mathrm{P}} \cdot \overrightarrow{\mathrm{Q}}=0P⋅Q=0
∣P⃗×Q⃗∣=PQ|\vec{P} \times \vec{Q}|=P Q∣P×Q∣=PQ
P⃗⋅Q⃗=−PQ\vec{P} \cdot \vec{Q}=-P QP⋅Q=−PQ
