2/1+(3/1+3/2)+(4/1+4/2+4/30+(5/1+5/2+5/3+5/4)+...(50/1+50/2+50/3+...50/49)等于多少?
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![2/1+(3/1+3/2)+(4/1+4/2+4/30+(5/1+5/2+5/3+5/4)+...(50/1+50/2+50/3+...50/49)等于多少?](/uploads/image/z/43826-50-6.jpg?t=2%2F1%2B%283%2F1%2B3%2F2%29%2B%284%2F1%2B4%2F2%2B4%2F30%2B%285%2F1%2B5%2F2%2B5%2F3%2B5%2F4%29%2B...%2850%2F1%2B50%2F2%2B50%2F3%2B...50%2F49%29%E7%AD%89%E4%BA%8E%E5%A4%9A%E5%B0%91%3F)
2/1+(3/1+3/2)+(4/1+4/2+4/30+(5/1+5/2+5/3+5/4)+...(50/1+50/2+50/3+...50/49)等于多少?
2/1+(3/1+3/2)+(4/1+4/2+4/30+(5/1+5/2+5/3+5/4)+...(50/1+50/2+50/3+...50/49)等于多少?
2/1+(3/1+3/2)+(4/1+4/2+4/30+(5/1+5/2+5/3+5/4)+...(50/1+50/2+50/3+...50/49)等于多少?
n/1+n/2+……+n/(n-1)
=n/[2/n(n-1)]
=2/(n-1)
所以原式=2/1+2/2+2/3+……+2/49
=2/(1+2+……+49)
=2/1225