When summing from n=0, it means that the first term is n=0, and then the value of n is gradually increased. In this case, the summation expression of infinite series can be written as:
S = a0 + a 1 + a2 + a3 + ...
Where a0 is the term when n=0, a 1 is the term when n= 1, and so on.
When the sum starts from n= 1, it means that the first term is n= 1, and then the value of n gradually increases. In this case, the summation expression of infinite series can be written as:
S = a 1 + a2 + a3 + a4 + ...
Where a 1 is the first term, a2 is the term when n=2, and so on.
It should be noted that the choice of summing from n=0 or from n= 1 depends on specific problems and application scenarios. In some cases, it is more convenient to sum from n= 1, while in other cases, it is more appropriate to sum from n=0.