简单
1/(1*3)=(1/1-1/3)/2;
1/(3*5)=(1/3-1/5)/2;
1/(5*7)=(1/5-1/7)/2;
1/(7*9)=(1/7-1/9)/2;
1/(9*11)=(1/9-1/11)/2;
……
1/(95*97)=(1/95-1/97)/2;
1/(97*99)=(1/97-1/99)/2;
所以:
原式=(1/1-1/3)/2+(1/3-1/5)/2+(1/5-1/7)/2+……+(1/95-1/97)/2+(1/97-1/99)/2
=(1/1-1/3+1/3-1/5+1/5-1/7+1/7-……-1/97+1/97-1/99)/2
=(1/1-1/99)/2
=(98/99)/2
=49/99
估计你能问出这种题,也就能看懂这些步骤了.