设A1=2,An+1=1/2[An+(1/An）],求An是否收敛?注：不会弄下标,所以小写代表下标.An+1=1/2[An+(1/An）]>=1且An+1-An=1/2[An-(1/An）]

设数列{an}中,a1=2,an+1=an+n+1,则通项an=? 设a1,a2,...,an都是正数,证明不等式(a1+a2+...+an)[1/(a1)+1/(a2)+...+1/(an)]>=n^2 设数列,a1=3,an+1=3an-2,求数列an是等比数列 设数列AN满足A1等于1,3(A1+a2+~+AN)=(n+2)an,求通向公式 设数列{an}满足a1=1, an=(4an-1 +2)/(2an-1 +7) ,则通项xn=? 数列{An}满足a1=1/2,a1+a2+..+an=n方an,求an 数列an中,a1=3,an+1=an/2an+1,则an=? 数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1设Sn=1/a1+1/a2+...+1/an,n>2证明1 设数列【an】满足a1=1,3（a1+a2+a3+······+an）=（n+2）an,求通项an 设数列｛an}满足a1=2,an+1=an+1/an(n=1,2,3.),证明：an>根号下（2n+1).急用 已知数列{an},{bn}满足a1=2,2an=1+2an*an+1,设{bn}=an-1求数列{1n}为等差数列急！！！ 设数列{an}中,若an+1 =an+ an+2 (n∈N*),则称数列{an}为“凸数列” .设数列{an}为“凸数列”求第二问证明设数列{an}中,若an+1 =an+ an+2 (n∈N*),则称数列{an}为“凸数列” .设数列{an}为“凸数列”,若a1 =1, 数列AN满足A1=2,AN+1=AN^2+6AN+6,设CN=LOG5(AN+3),证｛CN}为等比 设a1=5,当n≥2时an+an-1=7/(an-an-1)+6,求数列(an)的通项公式 设数列{an}中,a1=1且an+1=3an+4,求证{an+2}是等比数列求{an}的前n项和为Sn 关于数列、等差数列的题目设数列an满足an+1=an-2且a1=241）判断an是什么数列2）若an 数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1 设Sn=1/a1+1/a2+...+1/an,n>2数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1设Sn=1/a1+1/a2+...+1/an,n>2证明1 设数列{an},a1=2,a（n+1）=an+In·（1+1/n）,求an