Tính giá trị của tổng \(T = C_{2019}^1 + C_{2019}^2 + C_{2019}^3 + ... + C_{2019}^{2018}\).

* Hướng dẫn giải

Ta có :  \({\left( {1 + x} \right)^{2019}} = \sum\limits_{k = 0}^{2019} {C_{2019}^k{x^k}} \)

Thay \(x = 1\) ta có :

 \(\begin{array}{l}{2^{2019}} = \sum\limits_{k = 0}^{2019} {C_{2019}^k}  = C_{2019}^0 + C_{2019}^1 + C_{2019}^2 + ... + C_{2019}^{2018} + C_{2019}^{2018}\\ \Rightarrow C_{2019}^1 + C_{2019}^2 + ... + C_{2019}^{2018} = {2^{2019}} - C_{2019}^0 - C_{2019}^{2019} = {2^{2019}} - 2\end{array}\)

Chọn B