so sánh :
a) \(\frac{3}{124};\frac{1}{41};\frac{5}{207}và\frac{2}{83}\)
b)\(\frac{16}{9}và\frac{24}{13}\)
c)\(\frac{27}{82}và\frac{26}{72}\)
so sánh A và B:
A=\(\frac{3^{123}+1}{3^{125}+1}\)
B=\(\frac{3^{122}+1}{3^{124}+1}\)
Áp dụng \(\frac{a}{b}< 1\Leftrightarrow\frac{a}{b}< \frac{a+m}{b+m}\) (a;b;m \(\in\)N*)
Ta có:
\(A=\frac{3^{123}+1}{3^{125}+1}< \frac{3^{123}+1+2}{3^{125}+1+2}\)
\(A< \frac{3^{123}+3}{3^{125}+3}\)
\(A< \frac{3.\left(3^{122}+1\right)}{3.\left(3^{124}+1\right)}\)
\(A< \frac{3^{122}+1}{3^{124}+1}=B\)
=> A < B
\(9A=\frac{3^{125}+9}{3^{125}+1}=1+\frac{8}{3^{125}+1}\)
\(9B=\frac{3^{124}+9}{3^{124}+1}=1+\frac{8}{3^{124}+1}\)
Mà 3^125+1>3^124+1 =>\(\frac{8}{3^{125}+1}< \frac{8}{3^{124}+1}\)
Nên A<B
9A=\(\frac{3^{125}+9}{3^{125}+1}\)=\(1+\frac{8}{3^{125}+1}\)
9B=\(\frac{3^{124}+9}{3^{124}+1}\)=\(1+\frac{8}{3^{124}+1}\)
Vì \(\frac{8}{3^{125}+1}< \frac{8}{3^{124}+1}\)\(\Rightarrow9B>9A\)\(\Rightarrow B>A\)
Vậy B>A
So sánh: \(\frac{3}{124},\frac{1}{41},\frac{2}{83},\frac{5}{207}\)
1/41>3/124>5/207>2/83
Ta co
3/124=30/1240
1/41=30/1230
5/207=30/1242
2/83=30/1245
k cho mik nha!
so sánh: A= \(\frac{3^{123}+1}{3^{125}+1}\)và B= \(\frac{3^{122}}{3^{124}+1}\)
các bn lm nhanh hộ mik, mik đang cần gấp
\(B=\frac{3^{122}}{3^{124}+1}=\frac{3^{123}}{3^{125}+3}< \frac{3^{123}+1}{3^{125}+3}< \frac{3^{123}+1}{3^{125}+1}=A\)
Do đó \(A>B\).
So sánh: \(\frac{73}{127}và\frac{75}{124}\)
nguyen thanh tung: dê già, dê cụ, biến thái, mất dạy,
Đồ là sự lỗi lầm của tạo hóa khi sinh ra một đứa không có giáo dục.
SO SÁNH : A = 3^123 +1 / 3^125 + 1 và B = 3^122/ 3^124 + 1
A = \(\dfrac{3^{123}+1}{3^{125}+1}\) Vì 3123 + 1 < 2125 + 1 Nên A = \(\dfrac{3^{123}+1}{3^{125}+1}\)< \(\dfrac{3^{123}+1+2}{3^{125}+1+2}\)
A < \(\dfrac{3^{123}+3}{3^{125}+3}\) = \(\dfrac{3.\left(3^{122}+1\right)}{3.\left(3^{124}+1\right)}\) = \(\dfrac{3^{122}+1}{3^{124}+1}\) = B
Vậy A < B
So sánh :
a)\(\frac{3}{124},\frac{1}{41},\frac{5}{207},\frac{2}{83}\)
b)\(\frac{-2525}{2929}và\frac{-217}{245}\)
c)\(A=\frac{3^{10}+1}{3^9+1}vàB=\frac{3^9+1}{3^8+1}\)
d)\(\frac{27}{82}và\frac{26}{75}\)
So sánh:
\(\frac{3}{124},\frac{1}{41},\frac{2}{83},\frac{5}{207}\)
\(\frac{-2525}{2929}v\text{à}\frac{-217}{245}\)
SO SÁNH A = 3^123 + 1 / 3^125 + 1 và B = 3^122+1 / 3^124+1
SO SÁNH : A = 3^123 +1 / 3^125 + 1 VÀ B = 3^122 + 1 / 3^124 + 1
so sánh : A = \(124.\left(\frac{1}{1.1985}+\frac{1}{2.1986}+\frac{1}{3.1987}+...+\frac{1}{16.2000}\right)\)
B=\(\frac{1}{1.17}+\frac{1}{2.18}+\frac{1}{3.19}+...+\frac{1}{1984.2000}\)
\(A=124\left(\frac{1}{1.1985}+\frac{1}{2.1986}+\frac{1}{3.1987}+...+\frac{1}{16.2000}\right)\)
\(=\frac{124}{1984}.\left(1-\frac{1}{1985}+\frac{1}{2}-\frac{1}{1986}+...+\frac{1}{16}-\frac{1}{2000}\right)\)
\(=\frac{1}{16}\left[\left(1+\frac{1}{2}+...+\frac{1}{16}\right)-\left(\frac{1}{1985}+\frac{1}{1986}+...+\frac{1}{2000}\right)\right]\)
Và \(B=\frac{1}{1.17}+\frac{1}{2.18}+...+\frac{1}{1984.2000}\)
\(=\frac{1}{16}\left[\left(1-\frac{1}{17}+\frac{1}{2}-\frac{1}{18}+...+\frac{1}{1984}-\frac{1}{2000}\right)\right]\)
\(=\frac{1}{16}\left[\left(1+\frac{1}{2}+...+\frac{1}{1984}\right)-\left(\frac{1}{17}+\frac{1}{18}+...+\frac{1}{2000}\right)\right]\)
= \(\frac{1}{16}\) . \(\left[\left(1+...+\frac{1}{16}\right)+\left(\frac{1}{17}+...+\frac{1}{1984}-\frac{1}{17}-...-\frac{1}{1984}\right)-\left(\frac{1}{1985}+...+\frac{1}{2000}\right)\right]\)
= \(=\frac{1}{16}\left[\left(1+\frac{1}{2}+...+\frac{1}{16}\right)-\left(\frac{1}{1985}+\frac{1}{1986}+...+\frac{1}{2000}\right)\right]\)
Vậy A = B