CMR : 1/3-2/3^2+3/3^3-4/3^4+...-2014/3^2014<1/5
2014+(2014/1+2)+(2014/1+2+3)+...+(2014/1+2+3+4+5+...+2013)=???.Ai giai duoc vay???
Bài 1 : Tính tổng
a) 1 *2 *3 + 2 * 3 *4 + 3 * 4 * 5 + ... + 2013 * 2014 * 2015 + 2014 * 2015 * 2016
b) 1 * + 3 * 4 + 5 * 6 + ... + 99 * 100
Bài 2 : CMR : 1^3 + 2^3 + 3^3 + ... + n^3 = ( 1 + 2 + 3 + ... + n )^2
A=2014+[2014:(1+2)]+[2014:(1+2+3)]+[2014:(1+2+3+4)]+...++[2014:(1+2+3+...+2013)]
Tính tổng:
A= 1+2014^1+2014^2+2014^3+...+2014^2014+2014^2015
B = 3-3^2+3^3+3^4+...+3^100
cm 1/3-2/3^2+3/3^3-4/3^4+.....-2014/3^2014<1/3
CMR:\(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+...-\frac{2014}{3^{2014}}<\frac{1}{5}\)
CMR:
\(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+...-\frac{2014}{3^{2014}}<\frac{1}{5}\)
Chứng minh: \(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+...-\frac{2014}{3^{2014}}<\frac{1}{5}\)
