Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 1:
Ta có:
\(\left(\frac{1}{10}\right)^{15}=\left(\frac{1}{5}\right)^{3.5}=\left(\frac{1}{125}\right)^5\)
\(\left(\frac{3}{10}\right)^{20}=\left(\frac{3}{10}\right)^{4.5}=\left(\frac{81}{10000}\right)^5\)
Lại có:
\(\frac{1}{125}=\frac{80}{10000}< \frac{81}{10000}\Rightarrow\left(\frac{1}{125}\right)^5< \left(\frac{81}{10000}\right)^5\)
\(\Rightarrow\left(\frac{1}{10}\right)^{15}< \left(\frac{3}{10}\right)^{20}\)
Bài 2:
Ta có:
\(A=\frac{13^{15}+1}{13^{16}+1}\Rightarrow13A=\frac{13^{16}+13}{13^{16}+1}=1+\frac{12}{13^{16}+1}\)
\(B=\frac{13^{16}+1}{13^{17}+1}\Rightarrow13B=\frac{13^{17}+13}{13^{17}+1}=1+\frac{12}{13^{17}+1}\)
Mà \(\frac{12}{13^{16}+1}>\frac{12}{13^{17}+1}\)
\(\Rightarrow1+\frac{12}{13^{16}+1}>1+\frac{12}{13^{17}+1}\)
\(\Rightarrow13A>13B\Rightarrow A>B\)
a) \(\frac{34}{13}=2\frac{8}{13}\)
Vì 2 > 1 nên \(2\frac{8}{13}>1\frac{7}{9}\)
hay \(\frac{34}{13}>1\frac{7}{9}\)
b) \(\frac{7}{9}=1-\frac{2}{9}\)
\(\frac{13}{15}=1-\frac{2}{15}\)
Vì \(\frac{2}{9}>\frac{2}{15}\) nên \(\frac{7}{9}< \frac{13}{15}\)
a) Ta có:
\(1\frac{7}{9}=\frac{16}{9}=\frac{208}{117}\)
\(\frac{34}{13}=\frac{306}{117}\)
Vì \(306>208\)
\(\Rightarrow\frac{306}{117}>\frac{208}{117}\)
\(\Rightarrow\frac{34}{13}>1\frac{7}{9}\)
b) Ta có:
\(\frac{7}{9}=\frac{35}{45}\)
\(\frac{13}{15}=\frac{39}{45}\)
Vì \(39>35\)
\(\Rightarrow\frac{39}{45}>\frac{35}{45}\)
\(\Rightarrow\frac{13}{15}>\frac{7}{9}\)
\(\frac{-16}{27}\)> \(\frac{-15}{29}\)
\(\frac{43}{-6}\)> \(\frac{-39}{8}\)
\(\frac{-16}{27}< \frac{-16}{29}< \frac{-15}{29}\)
\(\frac{43}{-6}< \frac{-43}{8}< \frac{-39}{8}\)
Ta có : 7/15 < 7/14 = 1/2. ( vì 15 > 14 )
20/39 > 20/40 = 1/2. ( vì 39 < 40 )
=> 7/15 < 1/2 < 20/39
hay 7/15 < 20/39.
Vậy..........
7*39=273 ; 20*15 =300
Vậy 7/15 < 20/39