观察下列等式,1/1*2=1-1/2,1/2*3=1/2-1/3,1/3*4=1/3-1/4,将以上3个等式两边分别相加,得,
1/1*2+1/2*3+1/3*4
=1-1/2+1/2-1/3+1/3-1/4
=1-1/4
=3/4.
猜想并写出:1/n(n+1)=1/n-1/(n+1)
直间写出下列各式的计算结果:
(1)1/1*2+1/2*3+1/3*4+…+1/2011*2012=2011/2012
(2)1/1*2+1/2*3+1/3*4+...+1/n(n+1)=n/(n+1)
(3)探究并计算:
1/2*4+1/4*6+1/6*8+...+1/2010*2012
=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+……+1/2010-1/2012)
=1/2*(1/2-1/2012)
=1/2*1005/2012
=1005/4024