Các câu hỏi tương tự
Tìm x biết
a) \(\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2019}\right).x=\frac{2018}{1}+\frac{2017}{2}+\frac{2016}{3}+...+\frac{2}{2017}+\frac{1}{2018}\)
b) \(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{2017}{2019}\)
\(A=\left(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2019}}\right):\left(1-\frac{1}{2^{2019}}\right)\)
Thực hiện phép tính (hợp lí nếu có thể):1,frac{-1}{3}-frac{-3}{5}-frac{1}{6}+frac{1}{43}-frac{-3}{7}+frac{-1}{2}-frac{1}{35}
2,left(-frac{1}{3}+frac{7}{13}right)-left(frac{-16}{24}+frac{6}{26}+frac{9}{13}right)3,frac{-7}{3}-left[frac{2}{5}-left(frac{1}{3}+frac{-5}{25}right)right]
4,left(2frac{1}{4}-3frac{1}{5}right)-left[frac{-3}{4}+left(frac{4}{5}-2019right)right]
Đọc tiếp
Thực hiện phép tính (hợp lí nếu có thể):
\(1,\frac{-1}{3}-\frac{-3}{5}-\frac{1}{6}+\frac{1}{43}-\frac{-3}{7}+\frac{-1}{2}-\frac{1}{35}\\ \\ 2,\left(-\frac{1}{3}+\frac{7}{13}\right)-\left(\frac{-16}{24}+\frac{6}{26}+\frac{9}{13}\right)\)\(3,\frac{-7}{3}-\left[\frac{2}{5}-\left(\frac{1}{3}+\frac{-5}{25}\right)\right]\\ 4,\left(2\frac{1}{4}-3\frac{1}{5}\right)-\left[\frac{-3}{4}+\left(\frac{4}{5}-2019\right)\right]\)
Cho b=\(1-\frac{2017}{2019}+\left(\frac{2017}{2019}\right)^2-\left(\frac{2017}{2019}\right)^3+...+\left(\frac{2017}{2019}\right)^{2020}\)
Cmr b<0
17 tháng 3 2019 lúc 22:58
Tìm x, biết:
a) \(x-\left\{\left[-x-\left(x+3\right)\right]-\left[\left(x+2018\right)-\left(x+2019\right)\right]+21\right\}=2020\)
b) \(\frac{1}{x}-\left\{\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{2018.2020}\right\}=\frac{1}{2019}\)
Help me! ( tặng 2 - 3 tk )
\(\left(1-\frac{1}{1+2}\right).\left(1-\frac{1}{1+2+3}\right).....\left(1-\frac{1}{1+2+3+.....2019}\right)\)
các bạn giúp ình vói nhé thứ 2 là phải nộp rồi
Cảm ơn các bạn rất nhiều
Câu 1: Tính giá trị biểu thức sau
A=\(\left(-1\right).\left(-1\right)^2.\left(-1\right)^3.\left(-1\right)^4...\left(-1\right)^{2018}.\left(-1\right)^{2019}\)
Câu 2: Tìm x, biết
\(\frac{x+1}{2}=\frac{8}{x+1}\)
Cho A =\(1-\frac{1}{2}+\frac{1}{3}-\frac{1}{\text{4}}+...+\frac{1}{2017}-\frac{1}{2018}+\frac{1}{2019}\)
và B=\(\frac{1}{1010}+\frac{1}{1011}+\frac{1}{1012}+...+\frac{1}{2018}+\frac{1}{2019}\)
Tính \(\left(A-B-1\right)^{2019}\)
Tìm x biết
a) \(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)
b) \(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=1\frac{2017}{2019}\)