求数学简算题(1) 3-4+5-6+7……2001-2002+2003-2004+2005 (2) 1/16+2/16+3/16+4/16……+14/16+15/16+14/16+13/16……+2/16+1/16
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![求数学简算题(1) 3-4+5-6+7……2001-2002+2003-2004+2005 (2) 1/16+2/16+3/16+4/16……+14/16+15/16+14/16+13/16……+2/16+1/16](/uploads/image/z/97603-43-3.jpg?t=%E6%B1%82%E6%95%B0%E5%AD%A6%E7%AE%80%E7%AE%97%E9%A2%98%EF%BC%881%EF%BC%89+3-4%2B5-6%2B7%E2%80%A6%E2%80%A62001-2002%2B2003-2004%2B2005+%282%29+1%2F16%2B2%2F16%2B3%2F16%2B4%2F16%E2%80%A6%E2%80%A6%2B14%2F16%2B15%2F16%2B14%2F16%2B13%2F16%E2%80%A6%E2%80%A6%2B2%2F16%2B1%2F16)
求数学简算题(1) 3-4+5-6+7……2001-2002+2003-2004+2005 (2) 1/16+2/16+3/16+4/16……+14/16+15/16+14/16+13/16……+2/16+1/16
求数学简算题
(1) 3-4+5-6+7……2001-2002+2003-2004+2005
(2) 1/16+2/16+3/16+4/16……+14/16+15/16+14/16+13/16……+2/16+1/16
求数学简算题(1) 3-4+5-6+7……2001-2002+2003-2004+2005 (2) 1/16+2/16+3/16+4/16……+14/16+15/16+14/16+13/16……+2/16+1/16
3-4+5-6+7……2001-2002+2003-2004+2005
=(-1)+(-1)+(-1).+(-1)+2005
=(-1)*1001+2005
=-1001+2005
=1004
1/16+2/16+3/16+4/16……+14/16+15/16+14/16+13/16……+2/16+1/16
=(1/16+14/16)+(2/16+13/16).+(2/16+13/16)+(1/16+14/16)+15/16+7/16*2
=15/16*12+14/16
=194/16
等差数列前n项和的通项公式 ;
(1)Sn=3+5+7+.....+2003+2005-3-5-....2002-2004=1002*3+1002*(1002-1)/2*2=1006008-1005004=1004
(2)Sn=(1+2+3+。。。。。+14)*2/16+15/16=(14+14*13/2)*2/16+15/16=225/16