1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6.+1/48*49*50怎么做啊

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1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6.+1/48*49*50怎么做啊1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6.+1/48*49*50怎么做啊1/1*2*

1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6.+1/48*49*50怎么做啊
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6.+1/48*49*50怎么做啊

1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6.+1/48*49*50怎么做啊
1/(1×2×3)+1/(2×3×4)+1/(4×5×6)、、、、+1/(48×49×50)= 1/2 *[(3-1)/(1*2*3)+(4-2)/(2*3*4).+(50-48)/(48*49*50)] =1/2 * [1/(1*2)-1/(2*3)+1/(2*3)-1/(3*4).+1/(48*49)-1/(49*50)] =1/2*(1/2-1/2450)=306/1225

1/(n-1)n(n+1)可以化为(1/n(n-1)-1/n(n+1))/2, 原式=(1/1*2-1/2*3+1/2*3-1/3*4......1/48*49-1/49*50)/2 =(1/2-1/2450)/2 =306/1225