add factorising notes for methods

diff --git a/chem/hdpe.pdf b/chem/hdpe.pdf
index 1c9576ab80b521dfd7ca5fc7385c64df651da800..b5facf485b34c66b66cfa4659e283f780936030c 100644 (file)
Binary files a/chem/hdpe.pdf and b/chem/hdpe.pdf differ