Question:
Explain why (a x b)•b=0
Solution:
A vector product n is always orthogonal to the 2 components. The phase angle between the vector product and any one of the 2 components is always 90 degrees.
So we have n • a = 0 and n • b = 0
Another question:
What is meant by skew lines?
Solution:
Given any 2 or more straight lines in 3D plane, they are skew if they never intersect, i.e. the system of the equations of the straight lines is inconsistent.