1. I don't understand this term: -1/sqrt 6 (5)

Do you mean

-1/(sqrt(6)* (5)) .....or: -1/(sqrt(6)) * (5) .....or: (-1/(sqrt(6)) * (5) .....or: -1/sqrt((6)* (5))

................or: .................................................. .or:

2. To help you with your calculations please post thecompletequestion, especially the vectors with their components, and your own work.