Tính:
A= 2014 + \(\frac{2014}{1+2}+\frac{2014}{1+2+3}+\frac{2014}{1+2+3+4}+........+\frac{2014}{1+2+3+4+.....+2013}\)
2014+(2014/1+2)+(2014/1+2+3)+...+(2014/1+2+3+4+5+...+2013)=???.Ai giai duoc vay???
(1/2012+1/2013-1/2014)/(5/2012+5/2013-5/2014)-(2/2103+2/2014-2/2015)/(3/2013+3/2014-3/2015)
2014 + 2014/(1+2) + 2014/(1+2+3) + ... + 2014/(1+2+...+2013)
1*2*3*4......2015-1*2*3*4...2014-1*2*3*4......2013*2014^2
1*2*3*4......2015-1*2*3*4...2014-1*2*3*4......2013*2014^2
1*2*3*...*2015-1*2*3*4*...*2014-1*2*3*...*2013*2014^2 tính nhanh
Tính nhanh
A = \(\left(\frac{2014}{2}+\frac{2014}{3}+\frac{2014}{4}+...+\frac{2014}{2015}\right):\left(\frac{2014}{1}+\frac{2013}{2}+\frac{2012}{3}+...+\frac{1}{2014}\right)\)
Tính Tổng:
A = 2014 + \(\frac{2014}{1+2}+\frac{2014}{1+2+3}+.....+\frac{2014}{1+2+3+...+2013}\)