gọi đó là A đi.
Ta có:
1/13+1/14+1/14< 1/12+1/12+1/12=3/12=1/4
1/61+1/62+1/63< 1/60+1/60+1/60=3/60=1/20
=> 1/5+1/13+1/14+1/15+1/61+1/62+1/63<1/5+1/4+1/20=1/2
=>A< 1/2 (ĐPCM)
CMR: 1/5 + 1/13 +1/14 +1/15 +1/61 +1/62 + 1/63 < 1/2
chứng minh rằng s=1/5+1/13+1/14+1/15+1/61+1/62+1/63<1/2
chứng minh 1/5+1/13+1/14+1/15+1/61+1/62+1/63 < 1/2
Chứng tỏ rằng : 1/5+1/13+1/14+1/15+1/61+1/62+1/63<1/2
CHỨNG MINH 1-(1/5 +1/13 +1/14+1/15+1/61 +1/62 +1/63) > 1/2
Chứng minh S = 1/5 +1/13+ /14+1/15+1/61+1/62+1/63 < 1/2
chứng minh rằng: S=1/5+1/13+1`/14+1/15+1/61+1/62+1/63<1/2
s= 1/5+1/13+1/14+1/15+1/61+1/62+1/63.CMR:3/7<S<1/2
cho M=1/5+1/13+1/14+1/15+1/61+1/62+1/63. Hãy so sánh M với 1/2
