1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]求和

来源:学生作业帮助网 编辑:六六作业网 时间:2025/01/04 03:44:14
1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]求和1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]求和1/(1*4)+

1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]求和
1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]求和

1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]求和
1/(1*4)+1/(4*7)+1/(7*10)+……+1/[(3n-2)(3n+1)]
=3(1-1/4+1/4-1/7+...+1/(3n-2)-1/(3n+1))
=3*(1-1/(3n+1))
=9n/3n+1