How to Read a Matrix Expression

Often we desire to apply sequences of operations to vectors. For instance, we might want to translate a point to the origin, rotate it about some vector, and then translate it back. In order to specify and interpret such sequences, you should become proficient at reading matrix expressions.

The expression
can be read in one of two ways depending on the associativity of the multiplication.

Associating the left part of the expression is interpreted as changing the basis while keeping the coordinates fixed

Associating the right part of the expression is interpreted as changing coordinates while keeping the basis fixed
Lecture 9   Slide 7   6.837 Fall '00