https://olm.vn/hoi-dap/detail/10863149136.html
bài này lần trước mik vừa trả lời lần trước
Chứng minh rằng :
\(\dfrac{3}{1^2.2^2}+\dfrac{5}{2^2.3^2}+\dfrac{7}{3^2.4^2}+...+\dfrac{19}{9^2.10^2}< 1\)
chứng minh rằng
\(\dfrac{3}{1^2.2^2}+\dfrac{5}{2^2.3^2}+\dfrac{7}{3^2.4^2}+...+\dfrac{19}{9^2.10^2}< 1\)
Cho biểu thức A=\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+\(\dfrac{1}{5^2}\)+\(\dfrac{1}{6^2}\)+\(\dfrac{1}{7^2}\)+\(\dfrac{1}{8^2}\)+\(\dfrac{1}{9^2}\)+\(\dfrac{1}{10^2}\)
Chứng minh rằng A<1
Tìm x \(3^3.x^2-2^4.x^2=8^2.5-4^2.3^2\)
\(\left[\left(\dfrac{1}{2}\right)^2-\left(\dfrac{1}{3}\right)^3\right]x+3^2.2^2=4^2.3\)
1. a) \(\dfrac{5}{3}\) . \(\dfrac{11}{7}\) - \(\dfrac{5}{7}\) . \(\dfrac{5}{3}\)
b) (0,125)\(^{16}\). (-8)\(^{16}\)
c) \(\dfrac{9^2.9^3}{3^9}\)
d) \(\dfrac{9}{24}\) - \(\dfrac{7}{41}\) + \(\dfrac{15}{24}\) + 0,75 - \(\dfrac{34}{41}\)
e) \(5\dfrac{2}{7}\) . ( \(-\dfrac{1}{3}\)) - \(2\dfrac{2}{7}\) . (\(-\dfrac{1}{3}\))
2. a) \(\dfrac{3}{4}\) + \(\dfrac{2}{3}x\) = \(\dfrac{1}{2}\)
b) (2x - 1)\(^2\) = 25
c) | x + 5 | - 6 = 9
Chứng minh rằng:
\(\dfrac{1}{4}\)+\(\dfrac{1}{11}\)+\(\dfrac{1}{18}\)+
\(\dfrac{1}{21}\)+\(\dfrac{1}{24}\)+\(\dfrac{1}{27}\)+\(\dfrac{1}{29}\) < \(\dfrac{4}{5}\)
\(\dfrac{help}{me}\)
cho \(A=\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+...+\dfrac{1}{9^2}\) chứng minh \(\dfrac{2}{5}< A< \dfrac{8}{9}\)
1/ Cho A= \(\dfrac{1}{3}\)-\(\dfrac{2}{3^2}\)+\(\dfrac{3}{3^3}\)-\(\dfrac{4}{3^4}\)+.....+\(\dfrac{99}{3^{99}}\)-\(\dfrac{100}{3^{100}}\) Chứng minh A < \(\dfrac{3}{16}\)
2/ Cho B=(\(\dfrac{1}{2^2}\)-1)(\(\dfrac{1}{3^2}\)-1)....(\(\dfrac{1}{100^2}\)-1) So sánh B và \(\dfrac{-1}{2}\)
Chứng minh rằng \(\dfrac{3}{1^2+2^2}+\dfrac{5}{2^2+3^2}+...+\dfrac{19}{9^2+10^2}\) < 1.
