How do I calculate vector magnitude with given coordinates?

[andydan1056]

Homework Statement

Homework Equations

magnitude of vector u = sqrt(u1^2 + u2^2 + u3^3)

The Attempt at a Solution

I'm not sure how to do this or draw a picture. Could someone show me how to do this? Thanks!

 

[BvU]

You can begin with a coordinate system. (PF rules require something of an effort is made by the requester...)