计算:1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+···+1/60+···59/60

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/04 05:49:34
计算:1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+···+1/60+···59/60

计算:1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+···+1/60+···59/60
计算:1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+···+1/60+···59/60

计算:1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+···+1/60+···59/60
1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+···+1/60+···59/60
=1/2+(1+2)/3+(1+2+3)/4.(1+2+3...+59)/60
=1/2+1+(1+1/2)+2+(2+1/2)...(29+1/2)
=(1+2+3...+29)*2+1/2*30
=870+15
=885

1/n +2/n +...+(n-1)/n = n(n-1)/2n=(n-1)/2
1/2+[1/3+2/3]+[1/4+2/4+3/4]+[1/5+2/5+3/5+4/5]+···+[1/60+···59/60]
= 1/2*[1+2+3+...+59]
=1/2[59*60/2]
=885

=1/2+3/3+6/4+(1+4)*4/2/5+(1+5)*5/2/6+(1+6)*6/2/7+...+(1+59)*59/2/60
=1/2+2/2+3/2+4/2+5/2+6/2+...+59/2
=(1+59)*59/2/2
=15*59
=15(60-1)=900-15
=885

1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+...+1/60+...+59/60
=1/2+(1+2)/3+(1+2+3)/4+(1+2+3+4)/5+...+(1+2+3+4+...+59)
=1/2+1+3/2+2+...+[(1+59)*59/2]/60
=1/2+1+3/2+2+...+59/2
=1/2+2/2+3/2+4/2+...+59/2
=[1+2+3+4+...+59]/2
=(1+59)*59/4
=15*59
=885.

1/2+2/2+3/2......+59/2
得出(1+2+3+4+5....+59)/2=885

答案是885
把分母相同的放在一起 组成一项 比如10 1/10 2/10 3/10......这些项相加是等于(n-1)/2 n是 分母值 n是从3开始算
这样的话结果就等于1/2 +∑(n-1)/2 这样再进行数列求和就可以得到
结果是885