1/2*4+1/4*6+1/6*8+…﹢1/98*100
问题描述:
1/2*4+1/4*6+1/6*8+…﹢1/98*100
答
1/2*4+1/4*6+1/6*8+…﹢1/98*100
=1/2﹙1/2-1/4+1/4-1/6+1/6-1/8+······+1/98-1/100﹚
=1/2﹙1/2-1/100﹚
=1/2×49/100
=49/200
答
1/2*4+1/4*6+1/6*8+…﹢1/98*100
=(1/2-1/4+1/4-1/6+1/6-1/8+……+1/98-1/100)/2
=(1/2-1/100)/2
=49/200