求2004*2002/2003 (1/15+2/17)*15*17 1/1*2+1/2*3+1/3*4+……+1/98*99+1/99*100

题目

求2004*2002/2003 (1/15+2/17)*15*17 1/1*2+1/2*3+1/3*4+……+1/98*99+1/99*100
求求了 急用!
求2004*(2002/2003)和(1/15+2/17)*15*17和(1/1*2)+(1/2*3)+(1/3*4)+……+(1/98*99)+(1/99*100)

答案

2004*2002/2003=(2003+1)(2003-1)/2003=(2003*2003-1)/2003=2003-1/2003 (1/15+2/17)*15*17=(17+2*15)/(15*17)*(15*17)=47 1/1*2+1/2*3+1/3*4+……+1/98*99+1/99*100∵1/1*2=1-1/2 1/2*3=1/2-1/3 1/3*4=1/3-1/4 ...