so we have: which we will call 1), 2), and 3) respectively.

now first subtract 2) from 1), then 3) from 2), and finally 1) from 3) to get:

and multiply the equations together:

which, since gives us:

this time multilpy 1) by , 2) by , and 3) by to get:

which we'll call 4), 5), and 6) respectively. now subtract 5) from 4), then 6) from 5) and finally 4) from 6)

to get: and multiply the equations together:

which, since gives us:

now by and thus: since so: and hence by