\(=\dfrac{199}{90}-3+\dfrac{1}{2}=-\dfrac{13}{45}\)
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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}
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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 \(\dfrac{-1}{2}\)
3dfrac{3}{3}.dfrac{1}{3}-dfrac{3}{4}.dfrac{1}{3}left[dfrac{11}{3}right]-left(dfrac{-1}{2}right)^2-4dfrac{1}{2}left(dfrac{3}{2}-dfrac{5}{4}+dfrac{1}{3}right):left(dfrac{4}{3}+2dfrac{3}{2}-dfrac{3}{4}right)5dfrac{5}{27}+dfrac{7}{23}+0,5+dfrac{-5}{27}+dfrac{16}{23}2dfrac{5}{4}+left(-2018right)^0-left[dfrac{-1}{4}right]dfrac{19}{11}.dfrac{6}{5}+dfrac{6^2}{11}.dfrac{6}{5}-left(dfrac{1}{2}right)^0
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\(3\dfrac{3}{3}.\dfrac{1}{3}-\dfrac{3}{4}.\dfrac{1}{3}\)
\(\left[\dfrac{11}{3}\right]-\left(\dfrac{-1}{2}\right)^2-4\dfrac{1}{2}\)
\(\left(\dfrac{3}{2}-\dfrac{5}{4}+\dfrac{1}{3}\right):\left(\dfrac{4}{3}+2\dfrac{3}{2}-\dfrac{3}{4}\right)\)
\(5\dfrac{5}{27}+\dfrac{7}{23}+0,5+\dfrac{-5}{27}+\dfrac{16}{23}\)
\(2\dfrac{5}{4}+\left(-2018\right)^0-\left[\dfrac{-1}{4}\right]\)
\(\dfrac{19}{11}.\dfrac{6}{5}+\dfrac{6^2}{11}.\dfrac{6}{5}-\left(\dfrac{1}{2}\right)^0\)
\(\left(\dfrac{-2}{3}\right)^2.x=\left(\dfrac{-2}{3}\right)^5\)
\(\left(x-\dfrac{1}{2}\right)^3=\dfrac{1}{27}\)
\(\left(\dfrac{2}{3}x-1\right)\left(\dfrac{3}{4}x+\dfrac{1}{2}\right)=0\)
\(\dfrac{4}{9}:x=3\dfrac{1}{3}:2,25\)
\(1\dfrac{1}{3}:0,8=\dfrac{2}{3}:0,1x\)
Tìm số nguyên x, biết:
a) -4dfrac{3}{5}. 2dfrac{4}{3} x -2dfrac{3}{5} : 1dfrac{6}{15}
b) -4dfrac{1}{3}.(dfrac{1}{2}-dfrac{1}{6}) x - dfrac{2}{3}.(dfrac{1}{3} - dfrac{1}{2} - dfrac{3}{4})
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Tìm số nguyên x, biết:
a) \(-4\dfrac{3}{5}\). \(2\dfrac{4}{3}\) < x < \(-2\dfrac{3}{5}\) : \(1\dfrac{6}{15}\)
b) \(-4\dfrac{1}{3}\).(\(\dfrac{1}{2}\)-\(\dfrac{1}{6}\)) < x < - \(\dfrac{2}{3}\).(\(\dfrac{1}{3}\) - \(\dfrac{1}{2}\) - \(\dfrac{3}{4}\))
-2/5 : \(1\dfrac{1}{3}\)- ( 1/2 )\(^2\)
\(\left(\dfrac{1}{2}-\dfrac{2}{3}+\dfrac{5}{6}\right).\left(\dfrac{-3}{2}\right)^2\)
\(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right).\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\)
1/ 3 x (x - \(\dfrac{1}{2}\)) - 3 x (x - \(\dfrac{1}{3}\)) - (x - \(\dfrac{1}{2}\)) = 0
2/ \(\dfrac{-2x+1}{3}\) + \(\dfrac{1}{2}\) = \(\dfrac{-1}{3}\)
\(B=\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+...+\dfrac{1}{3^{2020}}+\dfrac{1}{3^{2021}}< \dfrac{1}{2}\)
14 tháng 9 2021 lúc 10:40
Tính hợp lí:
\(1-\dfrac{1}{2}+2-\dfrac{2}{3}+3-\dfrac{3}{4}-4-\dfrac{1}{3}-2-\dfrac{1}{2}-1\)
a,2.(dfrac{1}{4}+x)^3(-dfrac{27}{4})b,(x+dfrac{1}{2})^3:3dfrac{-1}{81}c,(dfrac{2}{3}-x)^21:dfrac{4}{9}d,(2x-dfrac{1}{5})^2+dfrac{16}{25}1e,(dfrac{2}{5}-3x)^2-dfrac{1}{5}dfrac{4}{25}
Đọc tiếp
a,2.(\(\dfrac{1}{4}\)+x)\(^3\)=(\(-\dfrac{27}{4}\))
b,(x+\(\dfrac{1}{2}\))\(^3\):3=\(\dfrac{-1}{81}\)
c,(\(\dfrac{2}{3}\)-x)\(^2\)=1:\(\dfrac{4}{9}\)
d,(2x-\(\dfrac{1}{5}\))\(^2\)+\(\dfrac{16}{25}\)=1
e,(\(\dfrac{2}{5}\)-3x)\(^2\)-\(\dfrac{1}{5}\)=\(\dfrac{4}{25}\)