Chapter 01. Matrices, Vectors, and Vector Calculus
Problem 03. Transformation Matrix
The problem asks you to
find a transformation matrix that satisfying some condition.
This problem gives (or assumes)
This matrix rotates a rectangular coordinate through an angle of 120 degrees about an axis making equal angles with the original one.
You should know about
1) Direction cosine 2) Transformation matrix
We can see the relation between the rotated and the original coordinates system. This picture shows that
So, the transformation matrix is