1/(1*4) + 1/(4*7) +1/(7*10)+1/(10*13) …… 1/(298*301)=
问题描述:
1/(1*4) + 1/(4*7) +1/(7*10)+1/(10*13) …… 1/(298*301)=
答
=1/3*(1-1/4)+1/3*(1/4-1/7)+……+1/3*(1/298-1/301)
=1/3*(1-1/4+1/4-1/7+……+1/298-1/301)
=1/3*(1-1/301)
=100/301