1∕1×2×3+1∕2×3×4+1/4×5×6+1/6×7×8+1/8×9×10=
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/06/06 21:05:37
1∕1×2×3+1∕2×3×4+1/4×5×6+1/6×7×8+1/8×9×10=
1∕1×2×3+1∕2×3×4+1/3×4×5+1/4×5×6+1/5×6×7+1/6×7×8+1/7×8×9+1/8×9×10
=1/2×(1∕1×2-1/2×3+1∕2×3-1/3×4+1/3×4-1/4×5+1/4×5-1/5×6+1/5×6-1/6×7+1/6×7-1/7×8+1/7×8-1/8×9+1/8×9-1/9×10)
=1/2×(1/1×2-1/9×10)
=1/2×(1/2-1/90)
=1/2×22/90
=11/90
=1/2×(1∕1×2-1/2×3+1∕2×3-1/3×4+1/3×4-1/4×5+1/4×5-1/5×6+1/5×6-1/6×7+1/6×7-1/7×8+1/7×8-1/8×9+1/8×9-1/9×10)
=1/2×(1/1×2-1/9×10)
=1/2×(1/2-1/90)
=1/2×22/90
=11/90
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20 =
1+2+3+4+5+6+7+8+9+10+11+12=?
(1+1∕2)(1+1∕2^2)(1+1∕2^4)(1+1∕2^8)
(1-1∕2)+(1∕2-1∕3)+(1∕3-1∕4)+…+(1∕1999+1∕2000)
设A=1+1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9 ……+1/16,求A的整数部分.
1×2分之一+2×3分之一+3×4分之一+4×5分之一+5×6分之一+6×7分之一+7×8分之一+8×9分之一+9×10
1+2-3+4+5-6+7+8-9+.+58+56-60等于几?
(1+2+3+4+5+6+7+8+9)X(2013+2014+2015)=
求1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10
1+2-3-4+5+6-7-8+9+.+78-79-80+81
(1+3+7+…+1991)-(2+4+6+8+…+1990)=
解分式方程[(x+2)/(x+1)]+[(x+8)/(x+7)]=[(x+6)]/[(x+3)]+[(x+4)}/[(x