1/[(2n-1)*(2n+1)*(2n+3)]=1/4[1/[(2n-1)*(2n+1)-1/[(2n+1)*(2n+3)]=]所以,
原始＝1/4*（1/1*3－1/3*5+1/3*5－1/5*7.+1/25*27-1/27*29]=1/4*(1/3-1/27*29)=65/783