\(25\cdot\left(\dfrac{-1}{5}\right)^3+\dfrac{1}{5}-2\cdot\left(\dfrac{-1}{2}\right)^2-\dfrac{1}{2}\)
\(=25\cdot\left(\dfrac{-1}{125}\right)+\dfrac{1}{5}-2\cdot\left(\dfrac{-1}{4}\right)-\dfrac{1}{2}\)
\(=\left(\dfrac{-1}{5}\right)+\dfrac{1}{5}-\left(\dfrac{-1}{2}\right)-\dfrac{1}{2}\)
\(=0\)
1.Tính A= \(\left(\dfrac{1}{2}-1\right)\cdot\left(\dfrac{1}{3}-1\right)\cdot\cdot\cdot\left(\dfrac{1}{2018}-1\right)\)
2. Tìm GTLN của B = \(-\left|2018\cdot x+1\right|+\dfrac{3}{13}\)
Tính nhanh :
\(\dfrac{\left(\dfrac{2}{3}\right)^3\cdot\left(-\dfrac{3}{4}\right)^2\cdot\left(-1\right)^5}{\left(\dfrac{2}{5}\right)^2\cdot\left(-\dfrac{5}{12}\right)^3}\)
Thực hiện tính
M=\(1+\dfrac{1}{2}\cdot\left(1+2\right)+\dfrac{1}{3}\cdot\left(1+2+3\right)+\dfrac{1}{4}\cdot\left(1+2+3+4\right)+...+\dfrac{1}{16}\cdot\left(1+2+3+...+16\right)\)
1)Thực hiện phép tính
a) \(\dfrac{9^8\cdot5^6}{3^7\cdot27^3\cdot25^4}\) b) \(\dfrac{5^{20}\cdot6^{18}}{15^{20}\cdot4^{10}}\) c) \(\left(\dfrac{1}{3}\right)^{50}\cdot9^{25}-\left(\dfrac{2}{3}\right)^{100}:\left(\dfrac{8}{27}\right)^{33}\) d) \(\left(\dfrac{3}{8}\right)^{60}\cdot\left(\dfrac{2}{3}\right)^{60}:\left(\dfrac{1}{2}\right)^{119}\cdot\left(\dfrac{1}{2}\right)\)
2) Tìm x, biết:
a) \(\dfrac{x}{12}=\dfrac{5}{x}\) b)\(8^x=2^{2x+3}\) c)\(\dfrac{1}{2}\sqrt{\dfrac{1}{2}x-2}-\dfrac{2}{3}=\dfrac{1}{3}\)
Tính hợp lý:
a, \(2008\cdot\left(\dfrac{1}{2007}-\dfrac{2009}{1004}\right)-2009\cdot\left(\dfrac{1}{2007}-2\right)\)
b,\(\dfrac{5^5\cdot20^3-5^4\cdot20^3+5^7\cdot4^5}{\left(20+5\right)^3\cdot4^5}\)
\(\dfrac{-8}{5}\cdot X-\dfrac{11}{5}\cdot X=2\cdot\left(X-1\right)\)
\(\dfrac{-4}{5}\cdot13\dfrac{1}{3}-\dfrac{4}{5}\cdot\left(-13\dfrac{1}{2}\right)\)Tính
tính B\(=\left(1-\dfrac{1}{1+2}\right)\cdot\left(1-\dfrac{1}{1+2+3}\right).....\left(1-\dfrac{1}{1+2+...+2018}\right)\)
\(\left[\dfrac{3}{7}\cdot\dfrac{4}{15}+\dfrac{1}{3}\cdot\left(9^{15}\right)\right]^0\cdot\dfrac{1}{3}\cdot\dfrac{6^8}{12^4}\). Tính
