\(C=\left(\dfrac{1}{2}-1\right)\left(\dfrac{1}{3}-1\right)\left(\dfrac{1}{4}-1\right).....\left(\dfrac{1}{2017}-1\right)\left(\dfrac{1}{2018}-1\right)\)
\(C=\dfrac{-1}{2}.\left(-\dfrac{2}{3}\right)\left(-\dfrac{3}{4}\right)....\left(-\dfrac{2017}{2018}\right)\)
\(C=-\dfrac{1}{2018}\) ( Vì dãy trên có 2017 số hạng)
Tính :
1, \(2016-1-\dfrac{1}{3}-\dfrac{1}{6}-\dfrac{1}{10}-\dfrac{1}{15}-...-\dfrac{1}{1225}\)
2, \(\dfrac{3}{2}+\dfrac{5}{4}+\dfrac{9}{8}+\dfrac{17}{16}+\dfrac{33}{32}+\dfrac{65}{64}-7\)
3, A= \(\dfrac{1}{3\cdot4}-\dfrac{1}{4\cdot5}-\dfrac{1}{5\cdot6}-...-\dfrac{1}{9\cdot10}\)
help me ~ mai mik phải nộp rồi
Bài 1: Thực hiện phép tính:
\(A=\left(-\dfrac{1}{125}\right)^{11}:\left(\dfrac{1}{5}\right)^{32}\)
\(B=1+\dfrac{1}{3}+\left(\dfrac{1}{3}\right)^2+....+\left(\dfrac{1}{3}\right)^{2018}\)
\(C=\dfrac{16^3\cdot3^{10}+120\cdot6^9}{4^6\cdot3^{12}+6^{11}}\)
\(D=\left(\dfrac{0.4-\dfrac{2}{9}+\dfrac{2}{11}}{1.4-\dfrac{7}{9}+\dfrac{7}{11}}-\dfrac{\dfrac{1}{3}-0.25+\dfrac{1}{5}}{1\dfrac{1}{6}-0.875+0.7}\right):\dfrac{2017}{2018}\)
\(E=\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}\)
\(G=\dfrac{\left(\dfrac{2}{5}\right)^7\cdot5^7+\left(2\dfrac{1}{4}\right)^3:\left(\dfrac{3}{16}\right)^3}{512+2^7\cdot5^2}:\dfrac{\left(\dfrac{1}{2}\right)^0}{\left(-1\right)^{2017}}\)
Mn ơi giúp e với ........ Em đang cần gấp giúp e với nha!!
Thank you mn nhiều nhiều.....
Cho biểu thức
A = \(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+..........+\dfrac{1}{2019}\)
B = \(\dfrac{2018}{1}+\dfrac{2017}{2}+\dfrac{2016}{3}+.......+\dfrac{1}{2018}\) Chứng tỏ rằng \(\dfrac{B}{A}\)là số nguyên
tìm x biết
a) \(\dfrac{1}{2}x+2\dfrac{1}{2}=3\dfrac{1}{2}x-\dfrac{3}{4}\)
b) \(\dfrac{2}{3}x-\dfrac{2}{5}=\dfrac{1}{2}x-\dfrac{1}{3}\)
c) \(\dfrac{1}{3}x+\dfrac{2}{5}\left(x+1\right)=0\)
d) \(\dfrac{2}{3}-\dfrac{1}{3}\left(x-\dfrac{3}{2}\right)-\dfrac{1}{2}\left(2x+1\right)=5\)
e) \(\dfrac{x+2015}{5}+\dfrac{x+2016}{4}=\dfrac{x+2017}{3}+\dfrac{x+2018}{2}\)
Bài 1 : Rút gọn biểu thức sau :
1, M = / x-1 / + x+2
2, N = x-3 + /x-3/
3, P = 22 - 1 - / x-2 /
Bài 2 : Cho :
A = \(1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}-\dfrac{1}{6}+...+\dfrac{1}{49}-\dfrac{1}{50}\)
Chứng minh rằng A < \(\dfrac{5}{6}\)
dấu / biểu diễn giá trị tuyệt đối nhé xin lỗi tớ ko biết viết dấu giá trị tuyệt đối
HELP ME ~ MAI MIK PHẢI NỘP RỒI ~ 
thực hiện các phép tính
a) \(-1\dfrac{1}{2}.21\dfrac{1}{3}+1\dfrac{1}{2}.1\dfrac{1}{3}\)
b) \(\dfrac{2018}{2019}.\left(13-13\dfrac{2018}{2019}\right)-\dfrac{1}{2019}:\dfrac{2019}{2018}\)
Điền số nguyên thích hợp vào ô vuông sau( phải giải thích)
a, \(\dfrac{1}{3}\)+\(\left(\dfrac{2}{4}-1\dfrac{2}{5}\right)\)<....<2\(\dfrac{1}{7}\)+\(\left(-\dfrac{2}{5}-\dfrac{1}{4}\right)\)
b,\(\dfrac{7}{3}\)+\(\left(\dfrac{3}{4}-\dfrac{1}{5}\right)\)>...>\(\dfrac{2}{3}+\left(-\dfrac{1}{4}+\dfrac{2}{7}\right)\)
help me, mai mình học T_T
tính
a) \(\left[\dfrac{0.8\div\left(\dfrac{4}{5}\cdot1025\right)}{0.64-1}+\dfrac{\left(1.08-\dfrac{2}{25}\right)\div\dfrac{4}{7}}{\left(6\dfrac{5}{7}-3\dfrac{1}{4}\right)\cdot2\dfrac{2}{17}}+\left(1.2\cdot0.5\right)\div\dfrac{4}{5}\right]\)
b) \(\left(0.2\right)^{-3}\left[\left(-\dfrac{1}{5}\right)^{-2}\right]^{-1}+\left[\left(\dfrac{1}{2}\right)^{-3}\right]^{-2}\div\left(2^{-3}\right)^{-1}-\left(0.175\right)^{-2}\)
c) \(2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\dfrac{1}{2}}}}\)
d) \(\dfrac{1}{90}-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-\dfrac{1}{3}\)
e) \(\left(\dfrac{1}{3}\right)^{-1}-\left(-\dfrac{6}{7}\right)^0+\left(\dfrac{1}{2}\right)^2\div2\)
f) \(\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}-\dfrac{2}{7}-\dfrac{2}{13}}\cdot\dfrac{\dfrac{3}{4}-\dfrac{3}{16}-\dfrac{3}{64}-\dfrac{3}{256}}{1-\dfrac{1}{4}-\dfrac{1}{16}-\dfrac{1}{64}}+\dfrac{5}{8}\)
g) \(\dfrac{1}{-\left(2017\right)\left(-2015\right)}+\dfrac{1}{\left(-2015\right)\left(-2013\right)}+...+\dfrac{1}{\left(-3\right)\cdot\left(-1\right)}\)
h) \(\left(1-\dfrac{1}{1\cdot2}\right)+\left(1-\dfrac{1}{2\cdot3}+...+\left(1-\dfrac{1}{2017\cdot2018}\right)\right)\)
1/\(4.\left(\dfrac{-1}{2}\right)^{^{ }3}+\dfrac{1}{2}:5\)
2/\(17\dfrac{1}{5}:\left(\dfrac{-5}{7}\right)-2\dfrac{1}{5}.\left(\dfrac{-7}{5}\right)\)
Help me