1/1*3+1/3*5+1/5*7.1/49*51

1/1*3+1/3*5+1/5*7.1/49*51
1/1*3+1/3*5+1/5*7.1/49*51

1/1*3+1/3*5+1/5*7.1/49*51
1/1*3+1/3*5+1/5*7+...+1/49*51
=1/2(1-1/3)+1/2(1/3-1/5)+...+1/2(1/49-1/51)
=1/2(1-1/3+1/3-1/5+.+1/49-1/51)
=1/2*(1-1/51)
=25/51
很高兴为您解答,OutsiderL夕为您答疑解惑
如果本题有什么不明白可以追问,手机客户端右上角评价点满意即可.

1/1*3+1/3*5+1/5*7+...+1/49*51
=1/2(1-1/3)+1/2(1/3-1/5)+...+1/2(1/49-1/51)
=1/2(1-1/3+1/3-1/5+....+1/49-1/51)
=1/2*(1-1/51)
=25/51

1/1*3+1/3*5+1/5*7.....1/49*51
=1/2(1-1/3+1/3-1/5+....+1/49-1/51)
=1/2(1-1/51)
=1/2*50/51
=25/51