عرض للطباعة
https://alnasiry.net/forums//uploaded/2_21mc17.png
https://alnasiry.net/forums//uploade...dcab3bf7f.jpeg
https://alnasiry.net/forums//uploaded/2_21mc19.jpg
(The vector PQ=Q-p=(3,3,3) length of vector PQ=3sqrt3 ( unit vector =(1/sqrt3,1/sqrt3,1/sqrt3)