hmm.. realized sometime when i read through the phy lists of definiton today.
it says a COUPLE is a pair of forces, equal in magnitude but opposite in direction and their lines of action do not coincide.
what i have always known is a couple is a pair of man n woman, equal in magnitude but opposite in gender and their lines of action do/does not coincide.
their lines of actions coincide as they are both human being, hence what man do woman can do, but it might not coincide when we talk about the functions of man n woman in society.
hah actually can link to the case of regression lines. assuming Y is the random variable : man n X the random variable : woma. if a regression line of Y on X is drawn n a regression line of X on Y is drawn n both line nearly coincides, it means their line of action coincide. and hence sugests a hjgh positive linear correlation b/w man n woman. but what if the lines are parallel or even have negative correlation, it would means they dun coincide and hence no fate b/w the couple.
... wth is wrong wif me, only a word of couple and i lame so much things... really need suntan more often before i go insane... muahah off to chem lect!!