-1\(a+2)(b+1)-1\(a+4)(b+3)-1\(a+100)(b+99)当a=2,b=1时,其值为多少?

问题描述:

-1\(a+2)(b+1)-1\(a+4)(b+3)-1\(a+100)(b+99)当a=2,b=1时,其值为多少?

-(1/4*2+1/6*4+...+1/102*100) =-(1/2-1/4+1/4-1/6...+1/100-1/102)*1/2 =-(1/2-1/102)*1/2 =-25/102