原式=(1+1/2)(1+1/3)(1+1/4)...(1+1/100)(1-1/2)(1-1/3)(1-1/4)...(1-1/100) =(3/2*4/3*5/4...*101/100) *( 2/3*3/4*4/5...*99/100) =(101/2 )*( 2/100) =101/100(此题只要知道a^2-b^2=(a+b)(a-b)就行了~~)
