Question by tth

30/10/2017 at 15:09

K = 1 + 3 + 7 + ... + 107

Dao Trong Luan Coordinator 30/10/2017 at 15:56

\(K=1+3+7+...+107\)

\(=\left(2^1-1\right)+\left(2^2-1\right)+\left(2^3-1\right)+...+\left(2^6-1\right)+107\)

\(=1+3+7+15+31+63+107=227\)
tth selected this answer.
Công Đinh 30/10/2017 at 18:36

K = 1 + 3 + 7 + ... + 107

K = ( 21 − 1) + ( 22 − 1 ) + ( 23 − 1 ) + ... + ( 26 − 1 ) + 107

K = 1 + 3 + 7 + 15 + 31 + 63 + 107

K = 227
Phan Thanh Tinh Coordinator 30/10/2017 at 16:40

We can't find the property of the terms of the sum