so sanh -17/35 va -43/85
so sanh 2 phan so khong qui dong
43/47 va 29/35
ta có
29/35<30/35=6/7=42/49
43/47>43/49
vì 29/35<42/49<43/49<43/47
nên 29/35<43/47
so sanh c va 5/6
c = 1/41+1/42+1/43+...+1/80
Cho hai phan so A=20/39 + 22/37 + 18/43 va B=14/39 + 22/29 + 18/41. So sanh A va B.
Ai nhanh nhat va dung nhat thi minh se tick va ket ban nhe!!!
so sanh 21^15 va 27^5
15^12 va 81^3.125^5
3^39 va 11^21
72^45-72^44 va 72^44-72^43
199^20 va 2003^15
a) \(21^{15}=21^{3.5}=\left(21^3\right)^5=9261^5\)
Vì \(9261>27\Rightarrow9261^5>27^5\Rightarrow21^{15}>27^5\)
b) \(15^{12}=\left(3.5\right)^{12}=3^{12}.5^{12}\)
\(81^3.125^5=\left(3^4\right)^3.\left(5^3\right)^5=3^{4.3}.5^{3.5}=3^{12}.5^{15}\)
Vì \(3^{12}=3^{12}\)mà \(5^{12}< 5^{15}\Rightarrow3^{12}.5^{12}< 3^{12}.5^{15}\Rightarrow15^{12}< 81^3.125^5\)
1/41+1/42+1/43+...+1/79 va 7/12( So sanh )
lam nhanh minh tick cho5 cai nha
ta có
7/12 = 4/12 +3 /12 = 1/3 + 1/4 = 20/60 + 20/80
1/41 + 1/42 + 1/43 + ....+ 1/79 + 1/80 = ( 1/41 + 1/42 + 1/43 + ...+1/60 ) + ( 1/61 + 1/62 + 1/63 + ...+ 1/79 + 1/80 )
do 1/41 > 1/42 > 1/43 > ... > 1/59 > 1/60
( 1/41 + 1/42 + 1/43 +...+ 1/60 ) > 1/60 + ..+ 1/60 = 20/60
và 1/61 >1/62>..1/80
( 1/61 + 1/62 + 1/63 + ...+ 1/80 ) > 1/80 +....+1/80 = 20/80
vậy 1/41 + 1/42 + 1/43 + .... + 1/79 + 1/80 > 20/60 + 20/80
1/41 + 1/42 + 1/43 + ..... + 1/79 + 1/80 > 7/12
7245 - 7244 va 7244 - 7243 . so sanh
So sanh
1/41 +1/42 + 1/4+1/43+...+1/79 va 7/12
lam nhanh minh tick
So Sanh
a) 72^54 - 72^24 va 72^44 - 72^43
b) 10^10 va 48 x 50^5
cac ban oi giup minh voi !!!!!