(1+1*2)-(2+5*6)+(3+1*12)-(4+19*20)+(5+1*30)-(6+41*42)+(7+1*56)-(8+71*72)+(9+1*90)

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/25 21:59:47
(1+1*2)-(2+5*6)+(3+1*12)-(4+19*20)+(5+1*30)-(6+41*42)+(7+1*56)-(8+71*72)+(9+1*90)(1+1*2)-(2+5*6)+(3+

(1+1*2)-(2+5*6)+(3+1*12)-(4+19*20)+(5+1*30)-(6+41*42)+(7+1*56)-(8+71*72)+(9+1*90)
(1+1*2)-(2+5*6)+(3+1*12)-(4+19*20)+(5+1*30)-(6+41*42)+(7+1*56)-(8+71*72)+(9+1*90)

(1+1*2)-(2+5*6)+(3+1*12)-(4+19*20)+(5+1*30)-(6+41*42)+(7+1*56)-(8+71*72)+(9+1*90)
原式=1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1+(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)
=2-1/10=19/10(或者1.9)

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