1X1/6+6X1/11+11X1/16……+10

1X1/6+6X1/11+11X1/16……+101X1/106=?

1个回答

1/1*6+1/6*11+1/11*16+...+1/101*106
=(1/5)*(1-1/6+1/6-1/11+1/11-1/16+...+1/101-1/106)
=(1/5)*(1-1/106)
=21/106