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 B=1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94
So sánh B 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 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=\(\frac{1}{3}+\frac{1}{16}+\frac{1}{19}+\frac{1}{21}+\frac{1}{61}+\frac{1}{72}+\frac{1}{83}+\frac{1}{94}\)
So sánh B với \(\frac{3}{5}\)
a) 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) Tính nhanh:
A = 2/3x5 + 3/5x8 +11/8x19 + 13/19x32 + 25/32x57 + 30/57x87
Mình đang cần gấp!!!!
a,Ta có :
1/3 + 1/16 + 1/19 + 1/21 + 1/61 + 1/72 + 1/83 + 1/94 = 0,54
3/4 = 0,6
=>b < 3/4
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=\(\frac{3}{5}\)
Ta có : 1/61 +1/72 +1/83 +1/94 < 1/60 x4 =1/15
1/16 +1/19 +1/21 < 1/15 x3 =3/15
1/3 =5/15
Do đó: B < 1/15 + 3/15 +5/15 = 9/15= 3/5
Vậy B< 3/5
\(\text{Bài giải}\)
\(\text{Ta có : }\)
\(B=\frac{1}{3}+\frac{1}{16}+\frac{1}{19}+\frac{1}{21}+\frac{1}{61}+\frac{1}{72}+\frac{1}{83}+\frac{1}{94}\)
B = 0,333333333 + 0,0625 + 0,0526315789 + 0,0476190476 + 0,0163934426 + 0,0138888889 + 0,0120481928 + 0,0106382979
B = 0,549052782
chứng minh:1/3+1/16+1/19+1/21+1/61+1/72+1/83+1/94<3/5
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