10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
来源:学生作业帮助网 编辑:作业帮 时间:2024/09/09 09:46:15
![10²-9²+8²-7²+6²-5²+4²-3²+2²-1²](/uploads/image/z/1024416-0-6.jpg?t=10%26%23178%3B%EF%BC%8D9%26%23178%3B%EF%BC%8B8%26%23178%3B%EF%BC%8D7%26%23178%3B%EF%BC%8B6%26%23178%3B%EF%BC%8D5%26%23178%3B%EF%BC%8B4%26%23178%3B%EF%BC%8D3%26%23178%3B%EF%BC%8B2%26%23178%3B%EF%BC%8D1%26%23178%3B)
x)34PS64~궀bp11\.fa$;5th[ fX@9DB~@2Fچ#]bmm3mSmmcm*d@*
3[tgv>ݾi뚧{tl545u4Jx6uӎ66=U
i/~6g5
*6$ف y-
10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
10²-9²+8²-7²+6²-5²+4²-3²+2²-1²
=(10+9)(10-9)+(8+7)(8-7)+……+(2+1)(2-1)
=10+9+8+7+6+5+4+3+2+1
=(10+1)*10/2
=55
========
附:平方差公式 a2-b2=(a+b)(a-b)
等差数列求和公式 (首项+末项)*项数/2