1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+.1/(1+2+3+4+5+6+.+50)=?

1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+.1/(1+2+3+4+5+6+.+50)=? -1/2,+1/3,-1/4,+1/5,-1/6,. (1/1+2)+(1/1+2+3)+...+(1/1+2+3+4+...+50) = (1+1/51)*(1-1/51) (1-1/2^2)(1-1/3^2)(1-1/4^2)(1-1/5^2)(1-1/6^2)(1\1/7^2)(1-1/8 6/1{4/1[3/1(2/1x-1)+3]+5}=1 解方程 1/6【1/4{1/3（1/2X-1）+3}+5】=1 1/2{1/3[1/4(1/5x-1)-6]+4}=1 1+2+3-4-5+1+1+2+3= (1+1/2+1/3+1/4+1/5)*(1/3+1/4+1)-(1+1/3+1/4)*(1/2+1/3+1/4+1/5 1+1+1+1+1+1+1+1+1+2+5+4+8+3+6+2+1+4等于多少? 1-1/2=1/2,1/2-1/3=1/6=1/2*3,1/3-1/4=1/12=1/3*4,1/4-1/5=1/20= 1/1×1/2×1/3+1/2×1/3×1/4+1/3×1/4×1/5+...+1/48×1/49×1/50