用简便方法计算1-2²+3²-4²+5²-6²+······+99²-100²
展开全部
用简便方法计算1-2²+3²-4²+5²-6²+······+99²-100²
解:原式=(3²-2²)+(5²-4²)+........+(99²-98²)+1-100²
=(3-2)×(3+2)+(5-4)×(5+4)+........+(99-98)(99+98)+1-100²
=5+9+...+197+1-100²
=(197+5)×49÷2+1-100²
=101×49+1-10000
=(100+1)×49+1-10000
=4949+1-10000
=-5050
解:原式=(3²-2²)+(5²-4²)+........+(99²-98²)+1-100²
=(3-2)×(3+2)+(5-4)×(5+4)+........+(99-98)(99+98)+1-100²
=5+9+...+197+1-100²
=(197+5)×49÷2+1-100²
=101×49+1-10000
=(100+1)×49+1-10000
=4949+1-10000
=-5050
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询