1/2*4+1/4*6+1/6*8+.+1/98*100怎样解?
1/2*4+1/4*6+1/6*8+.+1/98*100怎样解?
急
急
数学人气:246 ℃时间:2020-05-22 04:11:08
优质解答
因为1/n(n+2)=[1/n-1/(n+2)]/2所以1/2*4+1/4*6+1/6*8+.+1/98*100=1/2*(1/2-1/4)+1/2*(1/4-1/6)+1/2*(1/6-1/8)+...+1/2*(1/98-1/100)=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+...+1/98-1/100)=1/2*(1/2-1/100)=49/200.
我来回答
类似推荐
猜你喜欢
- 1英语字典CLEAN的音标
- 2英语连词成句及答案
- 3如何让30根牙签,4根吸管搭成高15cm的物体,而且可以在上面放书?
- 4Must I hand it in now?No,you___.You can hand it tomorrow.
- 5解不等式 (x2-4x+3)(x+2)小于0
- 6risk 的意思
- 7谁有300字关于雷锋助人为乐的作文
- 8In life,there is a person can go to miss,is the fate; There is a person can miss you,that is happiness.什么?
- 9一个最简分数,把它的分子扩大两倍,分母缩小三倍后等于3/4,这个分数原来是_.
- 10已知m²+m-1=0,求m³+2m²+3的值