六年级数学题1/(1*2*3)+1/(2*3*4)+1/(3*4*5)+1/(4*5*6)+1/(5*6*7)+.+1/(48*49*50)=?诉求,
问题描述:
六年级数学题1/(1*2*3)+1/(2*3*4)+1/(3*4*5)+1/(4*5*6)+1/(5*6*7)+.+1/(48*49*50)=?诉求,
答
=1/2*(1/1*2-1/2*3+1/2*3-1/3*4+……+1/48*19-1/49*50)
=1/2*(1/1*2-1/49*50)
=306/1225