If the sides of an angle are given by vectors `veca=hati-2hatj+2hatk and vecb=2hati+hatj+2hatk`, then find the internal bisector of the angle.

Explanation

A vector along the internal bisector is
`" "(veca)/(|veca|) + (vecb)/(|vecb|) = (hati - 2hatj +2hatk)/(3) + ( 2hati +hatj +2hatk)/(3)`
`" " = (1)/(3) ( 3hati -hatj + 4hatk )`