[A,BC] = [A,B]C + B[A,C]
This commutator product rule works just like the differentiation product rule:
assume that A is independent of C, you get the first term;
assume that A is independent of B, you get the second term.
— Me@2012-03-27 7:24:30 PM
2012.03.31 Saturday (c) All rights reserved by ACHK