\(\left(\frac{1}{2}-1\right)\left(\frac{1}{3}-1\right)\left(\frac{1}{4}-1\right)...\left(\frac{1}{2015}-1\right)\)
\(=>\frac{\left(-1\right)\left(-2\right)\left(-3\right)...\left(-2014\right)}{\left(2.3.4....2014\right).2015}=\frac{1}{1.2015}=\frac{1}{2015}\)
tính a: [1-1/2*2]*[1-1/3*3]*[1-1/4*4]*[1-1/5*5]*......*[1-1/2015*2015]*[1-1/2016*2016]
Tính C= 1+1/2(1+2)+1/3(1+2+3)+........+1/2015(1+2+3+4+...+2015)
Tinh:
S=2015 + 2015/1+2 +2015/1+2+3 + 2015/1+2+3+4 +... + 2015/1+2+3+...+2016
Tinh:
S=2015 + 2015/1+2 +2015/1+2+3 + 2015/1+2+3+4 +... + 2015/1+2+3+...+2016
Tinh tong S=1/1×2+1/2×3+1/3×4+...+1/2014×2015+1/2015×2016
A= ( 1/2017+ 2/2016+ 3/2015+...+ 2015/3+ 2016/2+ 2017) : ( 1/2+1/3+1/4+...+1/2017+1/2018)
Câu 1
a) Chứng tỏ rằng 1/3 - 1/3^2 + 1/3^3 - 1/3^4 + 1/3^5 - 1/3^6 < 1/4
b) Cho A= 2015^2016 + 2016^2015 x 2015 và B= 1 + 2^2 + 3^2 + ......+2016^2. Tính AB có chia hết cho 5 không? Vì sao?
Tinh tong S=1/1×2+1/2×3+1/3×4+...+1/2014×2015+1/2015×2016
A=(1/1009+1/1010+...+1/2015+1/2016):(1/1-1/2+1/3-1/4+...+1/2015-1/2016)
1/ Tính A= (1/2 + 1/3 + 1/4 +...+ 1/2016) : (2015/1 + 2014/2 + ...+ 1/2015)
