2つ の 新 の 数学 の法則 。。 過ぎ の 文章
Thm-1; Whats the sum of the coefficients in the expansion ..
..
Then we have sum-of-all-coefficients =
.
Also total possible combinations of n things is
.
Thm-2; In the above expansion the sum of odd coefficient is same as the sum of even coefficient. put x=-1, then from above;
1+∑even- coefficients = ∑odd-coefficients = 1/2(∑all-coefficients) =