Question

Answer 1

B=(1-2)(1+2)+(3-4)(3+4)+...+(2023-2024)

=-(1+2+3+4+...+2023+2024)

=-2023*2024/2=-2047276

Answer 2

\(B=1^2-2^2+3^2-4^2+...+2023^2-2024^2\)

\(B=\left(1-2\right)\left(1+2\right)+\left(3-4\right)\left(3+4\right)+...+\left(2023-2024\right)\left(2023+2024\right)\)

\(B=\left(-3\right)+\left(-7\right)+...+\left(-4047\right)\)

Số lượng số hạng:

\(\left(4047-3\right):4+1=1012\) (sh)

Tổng:

\(\left[\left(-4047\right)+\left(-3\right)\right]\cdot1012:2=-2049300\)