M=1+(-2)+(-2)2+....+(-2)2006
=> -2M=(-2)+(-2)2+(-2)3+....+(-2)2007
=> -2M-M=(-2)+(-2)2+(-2)3+...+(-2)2007)-(1+(-2)+(-2)2+...+(-2)2006)
=>-3M=(-2)+(2)2+(-2)3+...+(-2)2007-1-(-2)-(-2)2-...-(-2)2006
=(-2)2007-1
=>M=\(\frac{\left(-2\right)^{2007}-1}{-3}\)
tính M :N biết: N=1/2+1/3+1/4+......+1/2007+1/2008 và M= 2007/1+2006/2+2005/3+......+2/2006+1/2007
Tính :
\(\frac{\frac{2006}{2}+\frac{2006}{3}+\frac{2006}{4}+...+\frac{2006}{2007}}{\frac{2006}{1}+\frac{2006}{2}+\frac{2006}{3}+...+\frac{1}{2006}}\)
a,tính tổng : \(S=\dfrac{27+4500+135+550+2}{2+4+6+...+14+16+18}\)
b, So sánh : \(A=\dfrac{2006^{2006}+1}{2006^{2007}+1}v\text{à }B=\dfrac{2006^{2005}+1}{2006^{2006}+1}\)
M 20072 - 20062 + 20052 - 20042 + ...... - 22 + 12
tính M
tính hợp lí C=\(\frac{\frac{2006}{2}+\frac{2006}{3}+\frac{2006}{4}+...+\frac{2006}{2007}}{\frac{2006}{1}+\frac{2005}{2}+\frac{2004}{3}+...+\frac{1}{2006}}\)
c = 2005/2 + 2005/3+ 2005/4+....+ 2005/2005 , d = 2006 / 1 + 2006 / 2 + 2006 / 3 +....+ 4009 / 2004 tính c-d
c = 2005/2 + 2005/3+ 2005/4+....+ 2005/2005 , d = 2006 / 1 + 2006 / 2 + 2006 / 3 +....+ 4009 / 2004 tính c-d
c = 2005/2 + 2005/3+ 2005/4+....+ 2005/2005 , d = 2006 / 1 + 2006 / 2 + 2006 / 3 +....+ 4009 / 2004 tính c-d
Cho: A= 1/2 + 1/3 + 1/4+ ... +1/2008
B= 2007/1 + 2006/2 + 2005/3 +... +2/2006 + 1/2007
Tính B/A
