tình hợp lí:
\(\frac{\left(\frac{1}{5}-\frac{2}{7}\right)\cdot\frac{3}{4}-\frac{3}{4}\cdot\left(\frac{1}{3}-\frac{2}{7}\right)}{\frac{1}{5}\cdot\frac{2}{7}-\frac{1}{3}\cdot\left(\frac{2}{7}+\frac{3}{9}\right)+\frac{3}{9}+\frac{1}{5}}\)
\(\frac{1}{4028}< \left(\frac{1}{2}\cdot\frac{3}{4}\cdot\frac{5}{6}\cdot.......\cdot\frac{2011}{2012}\cdot\frac{2013}{2014}\right)^2< \frac{1}{2015}\)
Cho P\(=\frac{-1}{2}\cdot\frac{5}{9}\cdot x\cdot\frac{-7}{13}\cdot\frac{-3}{5}\)hỏi dấu của x là dấu dương hay âm khi
a)P<0
b)P=0
Cho P\(=\frac{-1}{2}\cdot\frac{5}{9}\cdot x\cdot\frac{-7}{13}\cdot\frac{-3}{5}\)hỏi dấu của x là dấu dương hay âm khi
a)P<0
b)P=0
Cho P\(=\frac{-1}{2}\cdot\frac{5}{9}\cdot x\cdot\frac{-7}{13}\cdot\frac{-3}{5}\)hỏi dấu của x là dấu dương hay âm khi
a)P<0
b)P=0
\(\left(\frac{1}{7}\cdot x-\frac{2}{7}\right)\cdot\left(-\frac{1}{5}\cdot x+\frac{3}{5}\right)\cdot\left(\frac{1}{3}\cdot x+\frac{4}{3}\right)=0\)
\frac{2}{1\cdot 3}+\frac{2}{3\cdot 5}+\frac{2}{5\cdot 7}+....+\frac{2}{29\cdot 31}
TÌM x biết:
a) \(\frac{1}{4}\cdot\frac{2}{6}\cdot\frac{3}{8}\cdot\frac{4}{10}\cdot\frac{5}{12}\cdot...\cdot\frac{30}{62}\cdot\frac{31}{62}=4^x\)
b) \(\frac{4^5+4^5+4^5+4^5}{3^5+3^5+3^5}\cdot\frac{6^5+6^5+6^5+6^5+6^5+6^5}{2^5+2^5}=8^x\)
c)\(\left|4x+3\right|-\left|x-1\right|=7\)
Tính :
\(A=1+\frac{2}{2^2}+\frac{3}{2^3}+\frac{4}{2^4}+\frac{5}{2^5}+\cdot\cdot\cdot\cdot+\frac{100}{2^{100}}\)