Các câu hỏi tương tự
CtR : 1/5+1/15+1/25+1/41+1/6+1/85+1/113 <1/2
CtR : 1/5+1/15+1/25+1/41+1/6+1/85+1/113 <1/2
CtR : 1/5+1/15+1/25+1/41+1/6+1/85+1/113 <1/2
CMR: 1/5+1/13+1/25+1/41+1/61+1/85+1/113<1/2
chung to : 1/5 + 1/16 + 1/25 + 1/41 + 1/60 + 1/85 + 1/113 < 1/2
so sánh A=1/5+1/13+1/25+1/41+1/61+1/85+1/113 với 1/2
chứng tỏ: a, 1/5 + 1/6 + 1/7 + .... + 1/17 < 2
b, 1/5 + 1/13 + 1/25 + 1/41 + 1/61 + 1/85 + 1/113 < 1/2
1- ( 1/5 +1/13+1/25+1/41+1/61+1/85+1/113)
So sánh với 1/2.
chung minh rang:
1/5+1/13+1/25+1/41+1/61+1/85+1/113<1/2