\(\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\left(\frac{2018}{2017}+\frac{2017}{2016}+\frac{2016}{2017}\right)\)
= \(\left(\frac{3-2-1}{6}\right)\left(\frac{2018}{2017}+\frac{2017}{2016}+\frac{2016}{2017}\right)\)
\(=0\cdot\left(\frac{2018}{2017}+\frac{2017}{2016}+\frac{2016}{2017}\right)=0\)
Bài đây dễ mà :vv
Câu 1. Tính hợp lý giá trị các biểu thức sau :
a. A = ( 689 - 31 ) - ( 269 - 131 )
b. B = \(\left(\frac{1}{2}+\frac{2016}{2017}+\frac{2017}{2018}+1\right)\times\left(\frac{2016}{2017}+\frac{2017}{2018}+\frac{3}{4}\right)-\left(\frac{1}{2}+\frac{2016}{2017}+\frac{2017}{2018}\right)\times\left(\frac{2016}{2017}+\frac{2017}{2018}+\frac{3}{4}+1\right)\)c. C = \(1-\frac{5}{6}+\frac{7}{12}-\frac{9}{20}+\frac{11}{30}-\frac{13}{42}+\frac{15}{56}-\frac{17}{72}+\frac{19}{90}\)
1+2+3+4+...+2016+2017+2018
1+2+3+4+...+2016+2017+2018
(-1/2+1/3+1/6)*(2016/2017+2017/2018)
A= ( 1/2017+ 2/2016+ 3/2015+...+ 2015/3+ 2016/2+ 2017) : ( 1/2+1/3+1/4+...+1/2017+1/2018)
cho A =1+2^2018+3^2017+4^2016+...+2018^2+2019,B=1+2^2017+3^2016+...+2017^2+2018,chứng tỏ giá trị biểu thức A-3B dương
tính
A=\(\frac{\frac{2017}{2}+\frac{2017}{3}+\frac{2017}{4}+...+\frac{2017}{2018}}{\frac{2017}{1}+\frac{2016}{2}+...+\frac{1}{2017}}\)
Cho A=1/2018+2/2017+3/2016+...+2017/2+2018
B=1/2+1/3+1/4+....+1/2019
Tính A/B
cho a=1/2+1/3+1/4+...+1/2018 và b=1/2017+2/2016+3/2015+...+2017/1. Tính a/b
tính 1+2-3-4+5+6-7-...+2014-2015-2016+2017+2018
