Before discussing series, it is necessary to give some brief consideration to

the notion of a sequence and its limit. In calculus, a sequence is an arrange-

ment of terms, either numbers or functions, in a definite order. Thus, 1, 1/2,

(1/2)2, (1/2)3, . . ., is a sequence of numbers and (1/x /1), (1/x /2)2, (1/x /3)3, . . ., is a sequence of functions. Changing the order of the terms in a sequence changes the sequence.