\(\frac{3}{10}+\frac{3}{90}+\frac{3}{324}+...+\frac{1}{1050}\)
Tính :
C = \(\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{2015}}\)
D = \(\frac{1}{4}+\frac{1}{12}+\frac{1}{36}+\frac{1}{108}+\frac{1}{324}+\frac{1}{972}\)
Tìm tập hợp các số x thuộc N sao cho
\(\frac{2}{3}+\frac{4}{35}< \frac{x}{105}< \frac{1}{7}+\frac{2}{5}+\frac{1}{3}\)
Tìm tập hợp x thuộc Z biết rằng:
\(\frac{-7}{15}+\frac{8}{60}+\frac{24}{90}< hoăc=\frac{x}{15}< hoặc=\frac{3}{5}+\frac{8}{30}+\frac{-4}{10}\)
Chứng minh :
a) \(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+...+\frac{99}{3^{99}}-\frac{100}{3^{100}}< \frac{3}{16}\) \(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}+\frac{4}{4^4}+...+\frac{99}{3^{99}}-\frac{100}{3^{100}}< \frac{3}{16}\)
b)\(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+...+\frac{1}{79}+\frac{1}{80}< \frac{7}{12}\)
c) Cho \(S=\frac{3}{10}+\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}\)
Chứng minh \(1< S< 2\)
tính hợp lí ( nếu có thể )
\(\frac{1}{3}.\frac{-6}{13}.\frac{-9}{10}.\frac{-13}{36}\)
\(\frac{-1}{3}.\frac{-15}{17}.\frac{34}{45}\)
\(\left(1-\frac{1}{5}\right).\left(\frac{-3}{10}+\frac{1}{5}\right)\)
\(A=\frac{1}{3}\times\frac{4}{5}+\frac{1}{3}\times\frac{6}{5}+\frac{2}{3}\)
\(11\frac{1}{4}-\left(2\frac{5}{7}+5\frac{1}{4}\right)\)
Bài 1: Thực hiện phép tính 1 cách hợp lý;
\(a\)) \(Cho\) B\(=\) \(\frac{\left(5-\frac{5}{13}+\frac{5}{19}-\frac{5}{27}\right).4024.4026}{\left(10-\frac{10}{13}+\frac{10}{19}-\frac{10}{27}\right).2012.2013}\)
\(b\)) \(Cho\)\(A\)\(=\)\(\frac{11}{210}-\left(\frac{16}{15.31}+\frac{13}{31.44}+\frac{13}{22.70}\right)\)
\(c\)) \(\frac{3}{200}-\frac{3}{110}-\frac{3}{90}-\frac{3}{72}-\frac{3}{56}-...-\frac{3}{2}\)
\(d\)) \(Cho\)\(C=\)\(\frac{\frac{1}{29}+\frac{1}{11}-\frac{1}{2013}}{\frac{1}{29}+\frac{1}{11}-\frac{1}{2013}+\frac{1}{11}.\frac{1}{29}.\frac{1}{2013}}+\frac{1}{11.2013+29.2013-318}\)
Mọi người ơi giúp mình với , mình đang cần gấp
tìm số x , biết :
a) \(\frac{2}{3}x-\frac{3}{2}x=\frac{5}{12}\)
b) \(\frac{2}{5}+\frac{3}{5}.\left(3x-3,7\right)=\frac{-53}{10}\)
c) \(\frac{7}{9}:\left(2+\frac{3}{4}x\right)+\frac{5}{9}=\frac{23}{27}\)
d) \(\frac{-2}{3}.x+\frac{1}{5}=\frac{3}{10}\)
e) \(\left|x\right|-\frac{3}{4}=\frac{5}{3}\)
f) \(\left|2x-\frac{1}{3}\right|+\frac{5}{6}=1\)
1) Tính :
a) A = ( \(1-\frac{1}{2}\) ) + ( \(1-\frac{1}{4}\) ) + ( \(1-\frac{1}{8}\) ) + .......+ ( \(1-\frac{1}{512}\) ) + ( \(1-\frac{1}{1024}\) )
b) B = ( \(\frac{5^3}{6}+\frac{5^3}{12}+\frac{5^3}{20}+\frac{5^3}{42}+\frac{5^3}{56}+\frac{5^3}{72}+\frac{5^3}{90}\) ) : \(\frac{1124.2247-1123}{1124+1123.2247}\)
c) C = \(\frac{1}{3}+\frac{1}{9}+\frac{1}{18}+\frac{1}{30}+......+\frac{1}{14850}\)
Tính tổng:
\(50+\frac{50}{3}+\frac{25}{3}+\frac{30}{4}+\frac{10}{3}+\frac{100}{6.7}+...+198
.
99\)
