把这题打开就可以发现如下规律:
1) 每组第一项
1+2/1+3/1+.+9/1= (1+9)*9/2 = 45
2) 一次类推2-9项:
-(0+1/2+2/2+3/2+.8/2) = -(1+8)*8/2/2=-18
+(1/3+2/3+.7/3) = + (1+7)*7/3/2 = 28/3
-(1/4+2/4+.6/4) = -(1+6)*6/4/2 = -21/4
+(1/5+2/5+.5/5) = +(1+5)*5/5/2 = 3
-(1/6+2/6+3/6+4/6)= -5/3
+(1/7+2/7+3/7)= 6/7
-(1/8+2/8)= -3/8
+ 1/9
所以合计为:
= 45-18+28/3-21/4+3-5/3+6/7-3/8+1/9
= 30+1517/504 = 33+5/504 = 33(5/504)=33.01