ABSTRACT
This is also written as
(ab)nan n
an1b
n
an2b2
n
an3b3 . . .bn
where the numbers
n
r
n !
(n r) ! r !
are called binomial coefficients. Table 1 gives some binomial coefficients.
n
r
anrbr
where a n
r0 signifies that the terms which follow are to be added (summed)
starting with r/0 and ending with r/n . Thus, for example,
4 r
a4rbr
a4
a3b
a2b2
ab3
b4,
so
(ab)4a44a3b6a2b24ab3b4,
where use has been made of the entries corresponding to n/4 in the above table.