1. The problem statement, all variables and given/known data The vector -i+j+k bisects the angle between the vector c and 3i+4j. Determine a unit vector along c. 2. Relevant equations 3. The attempt at a solution Taking the dot product of the two vectors (other than c) gives me the cosine of the angle = 1/5√3. This is also equal to the angle between the angle bisector and c. But now I can't take the dot product anymore as I don't know anything about c.