简算:1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40) = 急

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/03 21:02:24
简算:1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40) = 急

简算:1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40) = 急
简算:1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40) = 急

简算:1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40) = 急
1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40)
=1-1/2+1/2-1/3+1/3-1/4+...+1/39-1/40
=1-1/40
=39/40

1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+······+1/(39*40)
=1-1/2+1/2-1/3+1/3-1/4+...+1/39-1/40
=1-1/40
=39/40