1/2×4+1/4×6+1/6×8+...+1/2008×2010 探究并计算

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1/2×4+1/4×6+1/6×8+...+1/2008×2010 探究并计算
x)37:

1/2×4+1/4×6+1/6×8+...+1/2008×2010 探究并计算
1/2×4+1/4×6+1/6×8+...+1/2008×2010 探究并计算

1/2×4+1/4×6+1/6×8+...+1/2008×2010 探究并计算
1/2×4+1/4×6+1/6×8+...+1/2008×2010
1/2^2(1/1*2+1/2*3+1/3*4+...+1/1004*1005)
=1/4(1/2+1/2-1/3+1/3-1/4+...+1/1004-1/1005)
=1/4(1-1/1005)
=251/1005

1/2×4+1/4×6+1/6×8+...+1/2008×2010
1/2^2(1/1*2+1/2*3+1/3*4+...+1/1004*1005)
=1/4(1/2+1/2-1/3+1/3-1/4+...+1/1004-1/1005)
=1/4(1-1/1005)
=251/1005

1/2×4+1/4×6+1/6×8+...+1/2008×2010
=1/2x【(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+...+(1/2008-1/2010)】
=1/2x(1/2-1/2010)
=1/2x1004/2010
=251/1005