=1/3(1x2x3)+2x3+...+99x100
=1/3(1x2x3)+1/3(3x2x3)+...+99x100
=1/3(2x3x4)+3x4+...+99x100
=1/3(2x3x4)+1/3(3x3x4)+...+99x100
=1/3(3x4x5)+...+99x100
...
=1/3(99x100x101)
=333300
1x2+2x3+3x4+4x5……99x100=?
原式 =1\/3(1x2x3)+2x3+...+99x100 =1\/3(1x2x3)+1\/3(3x2x3)+...+99x100 =1\/3(2x3x4)+3x4+...+99x100 =1\/3(2x3x4)+1\/3(3x3x4)+...+99x100 =1\/3(3x4x5)+...+99x100 ...=1\/3(99x100x101)=333300
1x2十2x3十...十99x100等于多少
1X2+2X3+3X4+4X5+…+99X100 可以直接运用计算公式1\/3*(N-1)N(N+1) 计算出结果：1x2十2x3十...十99x100 =1\/3*99*100*101 =333300
1乘2+2乘3+3乘4+···+99乘100=?
1X2 +2X3 +3X4 +4X5 +……+99X100 = 99X100X101 \/3 = 333300
1乘2+2乘3+3乘4+4乘5+···+99乘100
这样一来，一直加到 99X100，就是 1X2 +2X3 +3X4 +4X5 +……+99X100 = 99X100X101 \/3 = 333300
计算1x2+2x3+3x4+4x5+...+99x100
3*4=3^2+3 ...99*100=99^2+99 于是原式=（1^2+2^2+3^2+...+99^2）+（1+2+3++...+99）1到99的平方和可以用平方和公式 sn= n(n+1)(2n+1)\/6(证明放在最后面)即：1^2+2^2+3^2+...+99^2=99*100*199\/6=328350 1+2+3+...+99=（1+99）99\/2=4950 因此 原...
帮忙简算此题:1X2+2X3+3X4+4X5+…+99X100
由1x2=1\\3x1x2x3 1x2+2x3=1\\3x2x3x4 1x2+2x3+3x4=1\\3x3x4x5 得到：原式=1\\3x99x100x101 =333300
1x2+2x3+3x4+4x5...99x100
1x2+2x3+3x4+4x5...99x100 =1\/3*1*2*3+1\/3*[2*3*4-1*2*3]+1\/3[3*4*5-2*3*4]+...+1\/3[99*100*101-98*99*100]=1\/3[1*2*3+2*3*4-1*2*3+3*4*5-2*3*4+...+99*100*101-98*99*100]=1\/3*99*100*101 =3300*101 =333300 公式：Sn=1*2+2*3+3*...
1x2+2x3+3X4…+99X100=?
n(n+1)=(1\/3) { n(n+1)(n+2) - (n-1)n(n+1) } 1x2+2x3+3x4+...99x100 = 1x2 + (1\/3) { (2x3x4 - 1x2x3) + (3x4x5 - 2x3x4) +...+(99x100x101 - 98x99x100) } = 1x2 + (1\/3) { 99x100x101 -1x2x3 } = (1\/3) 99x100x101 =333300 ...
1X2+2X3+3X4+4X5+5X6···99X100=( ) 这道题目怎么做?
原式等于=1x2+2x3+3x4+4x5+5x6+···+99x100 =[1x1+1]+[2x2+2]+[3x3+3]+[4x4+4]+...+[99x99+99]=1x1+2x2+3x3+4x4+...+99x99+(1+2+3+4+...+99)=99x(99+1)x(99x2+1)\/6+99x(99+1)\/2 =33x50x199+99x50 =333300请点击 采纳为答案 ...
1×2加2×3加3×4依此类推九十九×100等于多少
解：原式=101-(1+1\/2+1\/3+1\/4+..+1\/100)设S=1\/2+1\/3+1\/4+..+1\/99+1\/100则S是调和级数，调和级数是没有通项公式的，只能近似计算：当n很大时，有个近似公式：1+1\/2+1\/3+1\/4+1\/5++1\/n=γ+ln(n)γ叫做欧拉常数，γ=0.57721566490153286060651209ln(n)是n的自然对数（即...
