1-1/4=(1+1/2)X(1-1/2)=3/2X(1/2)1-1/9=(1+1/3)X(1-1/3)=4/3X(2/3)1-1/16=(1+1/4)X(1-1/4)=5/4X(3/4).....1-1/2500=(1+1/50)X(1-1/50)=51/50X(49/50)所以相乘以后化简得1/2X(51/50)=0.51
