1/1X3+1/3X5+1/5X7.....+1/49X51=? 要过程的
1为分子,1X3为分母
参考答案:=1/2(1-1/3)-1/2(1/3-1/5)+1/2(1/5-1/7).....+1/2(1/49-1/51)
=1/2(1-1/3+1/3-1/5+1/5......-1/49+1/49-1/51)
=1/2(1-1/51)
=1/2X50/51
=25/51
1为分子,1X3为分母
参考答案:=1/2(1-1/3)-1/2(1/3-1/5)+1/2(1/5-1/7).....+1/2(1/49-1/51)
=1/2(1-1/3+1/3-1/5+1/5......-1/49+1/49-1/51)
=1/2(1-1/51)
=1/2X50/51
=25/51