equation 2.9 and 2.10

[gregorianrants]

the error is on the left hand side of equations 2.9 and 2.10 on page 34

it is my understanding that

1. $^Ap$ means p with respect to cooridnate frame A.
2. $({{\hat x}_A},{{\hat y}_A})$ and $({{\hat x}_B},{{\hat y}_B})$ are in world co-ordinates.

if the above 2 facts are correct then equations 2.9 and 2.10 would give p in world co-ordinates. not wrt A and B as the superscripts on the left of 2.9 and 2.10 indicate.