\(\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+...+\frac{1}{768}=x\)
\(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+...+\frac{1}{768}+\frac{1}{1536}\)
,\(\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+............+\frac{1}{768}=???\)
Giúp mình với!!! Thankyou nhiều ^_^
Thank nha!!! nhờ bạn mik được 10 điểm
Kết quả của phép tính
\(\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+........+\frac{1}{768}\)
Cho :
\(A=\frac{19}{24}-\frac{1}{2}-\frac{1}{3}-\frac{7}{24}\)
\(B=\frac{7}{12}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}-\frac{5}{12}\)
a, Tính A và B
b, Tìm x biết A - x = B
a)
\(A=\left(\frac{19}{24}-\frac{7}{24}\right)-\left(\frac{1}{2}+\frac{1}{3}\right)\)
\(A=\frac{1}{2}-\frac{1}{2}+\frac{1}{3}\)
\(A=\frac{1}{3}\)
\(B=\left(\frac{7}{12}-\frac{5}{12}\right)+\left(\frac{5}{6}+\frac{1}{4}-\frac{3}{7}\right)\)
\(B=\left(\frac{1}{6}+\frac{5}{6}\right)+\frac{1}{4}-\frac{3}{7}\)
\(B=\frac{5}{4}-\frac{3}{7}\)
\(B=\frac{23}{28}\)
b)
\(x=A-B\)
\(x=\frac{1}{3}-\frac{23}{28}\)
\(x=\frac{-41}{84}\)
A=\(\left(\frac{19}{24}-\frac{7}{24}\right)+\left(-\frac{1}{2}-\frac{1}{3}\right)\)
A=\(\frac{1}{2}+-\frac{5}{6}\)=\(-\frac{1}{3}\)
B=\(\left(\frac{7}{12}+\frac{5}{6}+\frac{1}{4}-\frac{5}{12}\right)-\frac{3}{7}\)
B=\(\frac{5}{4}-\frac{3}{7}\)=\(\frac{23}{28}\)
A-x=B
(=)\(-\frac{1}{3}\)-x=\(\frac{23}{28}\)
(=)x=-97/84
Tìm tập hợp số nguyên x biết :
a) \(\frac{1}{2}-\left(\frac{1}{3}+\frac{1}{4}\right)
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+...+\frac{1}{96}.Tinh\)
Đặt \(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+.....+\frac{1}{96}\)
\(\Rightarrow\frac{1}{2}A=\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+.....+\frac{1}{192}\)
\(\Rightarrow A-\frac{1}{2}A=\frac{1}{3}-\frac{1}{192}\)
\(\Rightarrow\frac{1}{2}A=\frac{21}{64}\)
\(\Rightarrow A=\frac{21}{64}.2=\frac{21}{32}\)
Cậu nên nhớ máy móc : chỉ cần lấy 1 - 1/96 là ra ngay kết quả
Và kết quả = 95/96
Cách này luôn luôn ĐÚNG !!
\(\left(\frac{1}{4}x-1\right)+\left(\frac{5}{6}x-2\right)-\left(\frac{3}{8}x+1\right)=4,5
\)
=> \(\left(\frac{1}{4}x+\frac{5}{6}x-\frac{3}{8}x\right)-\left(1+2+1\right)=4,5\)
=>\(\frac{17}{24}x-4=4,5\)
=> \(\frac{17}{24}x=8,5\)
=> \(x=8,5:\frac{17}{24}\)
=> \(x=12\)
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\)
\(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\)
\(A+\frac{1}{96}=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{96}\)
\(A+\frac{1}{96}=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{48}\)
\(A+\frac{1}{96}=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{24}\)
...
\(A+\frac{1}{96}=\frac{1}{3}+\frac{1}{3}\Rightarrow A=\frac{2}{3}-\frac{1}{96}=\frac{2\cdot32-1}{96}=\frac{63}{96}=\frac{21}{32}\).
\(1\frac{13}{15}.0,75-\left(\frac{8}{15}+25\%\right).\frac{24}{47}-3\frac{12}{13}:3\)
Tìm x
\(4\frac{1}{3}.\left(\frac{1}{6}-\frac{1}{2}\right)\le x\le\frac{2}{3}.\left(\frac{1}{3}-\frac{1}{2}-\frac{3}{4}\right)\)
câu 1 : là -4
câu 2 : là -1
nếu đúng hãy cho mình 1 k đúng nhé