1/1×2=1-1/2 1/2×3=1/2-1/3 1/3×4=1/3-1/4...求1/2+1/6+1/12+1/20
1个回答
1/2+1/6+1/12+1/20+...+1/380=1-1/2+1/2-1/3+1/3-1/4+.+1/19-1/20
=1-1/20=19/20
相关问题
观察下列各式 1/6=1/2×3=1/2-1/3 1/12=1/3×4=1/3-1/4 1/20=1/4×5=1/4-1
计算(1+1/1×2)+(2+1/2×3)+(3+1/3×4)+……+(20+1/20×21)
计算:(1+[1/1×2])+(2+[1/2×3])+(3+[1/3×4])+…+(20+[1/20×21]).
有一系列等式:1×2×3×4+1=(12+3×1+1)2;2×3×4×5+1=(22+3×2+1)2;3×4×5×6+1
观察[1/1×2]=[1/2],[1/1×2]+[1/2×3]=[2/3],[1/1×2]+[1/2×3]+[1/3×4
1/1×2=1-1//2,1/2×3=1/2-1/3,1/3×4=1/3-1/4,……
1/1×2=1-1/2,1/2×3=1/2-1/3,1/3×4=1/3-1/4,···
[1/1×2]=1-[1/2],[1/2×3]=[1/2]-[1/3],[1/3×4]=[1/3]-[1/4].
(1+1/2)×(1-1/3)=3/2×2/3=1×(1+1/2)×(1+1/4)×(1-1/3)×(1-1/5)=3/
已知1/2=1-1/2,1/6=1/2×3=1/2-1/3,1/12=7/3×4=1/3-1/4