1949²-1950²+1951²-1952²+.+1997²-199
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/06 19:22:18
1949²-1950²+1951²-1952²+.+1997²-1998²+1999²=?
![1949²-1950²+1951²-1952²+.+1997²-199](/uploads/image/z/6870435-51-5.jpg?t=1949%26%23178%3B%EF%BC%8D1950%26%23178%3B%EF%BC%8B1951%26%23178%3B%EF%BC%8D1952%26%23178%3B%EF%BC%8B.%EF%BC%8B1997%26%23178%3B%EF%BC%8D199)
1949²-1950²+1951²-1952²+.+1997²-1998²+1999²
=1999^2-1998^2+1997^2-1996^2+……+1951^2-1950^2+1949^2
=(1999+1998+1997+1996+……+1951+1950)+1949^2
=(1950+1999)×50÷2+1949^2
=98725+1949^2
=98725+3798601
=3897326
=1999^2-1998^2+1997^2-1996^2+……+1951^2-1950^2+1949^2
=(1999+1998+1997+1996+……+1951+1950)+1949^2
=(1950+1999)×50÷2+1949^2
=98725+1949^2
=98725+3798601
=3897326
1949²-1950²+1951²-1952²+.+1997²-199
1949²-1950²+1951²-1952²+……+1997²-19
50²-49²+48²-47²+...+2²-1² 数学计算
2011²-2010²+2009²-2008²+…+3²-2²
2008²-2007²+2006²-2005²+…+2²-1
10²-9²+8²-7²+6²-5²+4²-3
10²-9²+8²-7²+6²-5²+4²-3
﹙a²+b²-1﹚²-4a²b²
计算50²-49²+48²-47²+…+4²-3²+2
一、100²-99²+98²-97²+96²-95²+……+
(1²+3²+5²+...+99²)-(2²+4²+6
巧算:50²-49²+48²-47²+……+2²-1²=?