1/1*3 + 1/3*5 + 1/5*7 + 1/7*9 +…… + 1/2005*2007
1/1*3 1/3*5 1/5*7 1/7*9 1/2005*2007 是分数
1/1*3 + 1/3*5 + 1/5*7 + 1/7*9 +…… + 1/2005*2007
1/1*3 1/3*5 1/5*7 1/7*9 1/2005*2007 是分数
1/1*3 + 1/3*5 + 1/5*7 + 1/7*9 +…… + 1/2005*2007
=1/2[(1-1/3)+(1/3-1/5)+(1/5-1/7)+......+(1/2005-1/2007)]
=1/2(1-1/3+1/3-1/5+1/5-1/7+.........+1/2005-1/2007)
=1/2(1-1/2007)
=1003/2007
1/1*3 + 1/3*5 + 1/5*7 + 1/7*9 +…… + 1/2005*2007
=1/2*[(1-1/3)+(1/3-1/5)+(1/5-1/7)+…… + (1/2005-1/2007)]
=1/2*(1-1/2007)
=1003/2007
1/1*3 + 1/3*5 + 1/5*7 + 1/7*9 +…… + 1/2005*2007
=1/2*[(1-1/3)+(1/3-1/5)+(1/5-1/7)+…… + (1/2005-1/2007)]
=1/2*(1-1/2007)
=1003/2007