1/1+(2/1-1/2)+(3/1-2/2+1/3)+(4/1-3/2+2/3-1/4)+...+(9/1-8/2+7/3-6/4+...+1/9)=?

2020-10-12 02:31

问题补充:
kx3k6
kx3k6 ·
0 0

原式= (1+2+...+9) 
-(1/2+2/2+3/2+...+8/2)
+(1/3+2/3+...+7/3)
-(1/4+2/4+...+6/4)
+(1/5+...+5/5)
-(1/6+...+4/6)
+(1/7+2/7+3/7)
-(1/8+2/8)
+1/9
=45-36/2+28/3-21/4+15/5-10/6+6/7-3/8+1/9
=33+5/504