Finding Angle Bisector Vector in R3 Given V and U

[supercali]

Homework Statement

given 2 vectors in R3 v(a,b,c), u(e,f,g) find the Angle Bisector vector

Homework Equations

The Attempt at a Solution

i just can't find the solution to this problem after working on it allot of time
please if you can help i am sure the solution is quite easy but i can't see it

 

[Dick]

Normalize u and v to the same length, then take their average. How would you show that bisects the angle created by u and v?