## 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.