1/2+(1/2+1/3)+(1/4+2/4+3/4)+...+(1/50+2/50+3/50+...+48/50+49/50).
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/02 17:40:24
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1/2+(1/2+1/3)+(1/4+2/4+3/4)+...+(1/50+2/50+3/50+...+48/50+49/50).
1/2+(1/2+1/3)+(1/4+2/4+3/4)+...+(1/50+2/50+3/50+...+48/50+49/50).
1/2+(1/2+1/3)+(1/4+2/4+3/4)+...+(1/50+2/50+3/50+...+48/50+49/50).
原式=1/2+1+3/2+2+...+50/2
=1/2+2/2+3/2+...+50/2
=(1+2+…+50)/2
=1275/2
用到1+2+…+n=(1+n)n/2这个公式
1225/2
原式=1/2+1+3/2+2+...+50/2
=1/2+2/2+3/2+...+50/2
=(1+2+…+50)/2
=1275/2
用到1+2+…+n=(1+n)n/2这个公式
应为
1/2+(1/3+2/3)+(1/4+2/4+3/4)+...+(1/50+2/50+3/50+...+48/50+49/50)1/2*(2-1)+
=1/2*(2-1)+1/2*(3-1)+1/2*(4-1)+...+1/2*(50-1)
=1/2*(1+2+3+..49)
=1/2*(1+49)*49/2
=612.5