1/15+1/35+1/63+1/99+1/143
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![1/15+1/35+1/63+1/99+1/143](/uploads/image/z/14446232-8-2.jpg?t=1%2F15%2B1%2F35%2B1%2F63%2B1%2F99%2B1%2F143)
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pi{*H/ȣsQo(Nq P=nh k
1/15+1/35+1/63+1/99+1/143
1/15+1/35+1/63+1/99+1/143
1/15+1/35+1/63+1/99+1/143
1/15+1/35+1/63+1/99+1/143
=1/2(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)
=1/2(1/3-1/13)
=5/39
=1/3*5+1/5*7+1/7*9+1/9*11+1/11*13
=1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13
=1/3-1/13
=10/39
原式=(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)/2=(1/3-1/13)/2=5/39
(1/3-1/5)/2=1/15.。。。。。。。。。。。
原式=1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13
=1/3-1/13
=10/39