ta có: 1/61>1/72>1/83>1/94=>1/16+1/72+1/83+1/94<1/61*4=1/15
1/16>1/19>1/21=>1/16+1/21+1/1/19<3*1/16<3*1/15=3/15
1/3=5/15
ta được: 1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94<4/15+3/15+5/15=9/15=3/5 (ĐPCM)
chứng minh:1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94<3/5
chung minh D=1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94< 3/5
Cho A=1/3 + 1/16 + 1/19 + 1/21 + 1/61 + 1/72 + 1/83 + 1/94
So sánh A với 3/5.
Cho A= 1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94
So sánh A với 3/5
Cho B=1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94
So sánh B với 3/5
B=1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94
So sánh B với 3/5 nêu cách giải nhé
Cho P= \(\frac{1}{3}+\frac{1}{16}+\frac{1}{19}+\frac{1}{21}+\frac{1}{61}+\frac{1}{72}+\frac{1}{83}+\frac{1}{94}\)
So sánh P với \(\frac{3}{5}\)
Bài 3
Cho B =\(\frac{1}{3}+\frac{1}{16}+\frac{1}{19}+\frac{1}{21}+\frac{1}{61}+\frac{1}{72}+\frac{1}{83}+\frac{1}{94}\)
So sánh B=\(\frac{3}{5}\)
Cho B=\(\frac{1}{3}+\frac{1}{16}+\frac{1}{19}+\frac{1}{21}+\frac{1}{61}+\frac{1}{72}+\frac{1}{83}+\frac{1}{94}\)
So sánh B với \(\frac{3}{5}\)
