设an=1/根号n+1+根号n,求a1+a2+a3+……+n48

设an=1/根号n+1+根号n,求a1+a2+a3+……+n48 设an=根号n+根号(n+1),求Sn=a1+a2+a3+...+an设an=根号n+1-根号n,求Sn=a1+a2+a3+...+an 设an=根号n+根号(n+1),求Sn=1/a1+1/a2+1/a3+...+1/an 设正数a1,a2,a3,···an成等差数列,求证:1/(根号a1+根号a2)+1/(根号a2+根号a3)+···+1/(根号an+a(n-1)==n/(根号a1+a(n+1) 设数列的前n项的和为sn,a1=2,根号sn-根号sn-1=根号2,求sn还要求an 已知数列满足a1=1,根号a（n-1）-根号an=根号an*a（n-1）,求an (1/an)-an=2根号n,且an>0(1)求数列｛an｝的通项公式,(2)证明a1+a2+……+an＜根号n an=1/根号n+1+根号n,a1+a2+a3= an=1/[根号(1+n)-根号n]则a1+a2+...a10= 若an是正项数列根号a1 + 根号a2+ .+ 根号an=n^2+3n则 (a1)/2+(a2)/3+.(an)/(n+1)=多少? 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 数列{an}满足a1=0且1/(1-an+1)-1/(1-an)=1.设bn=(1-根号an+1)/根号n,证明sn 在数列{an}中,a1=3,(根号an)-(根号an-1)-(根号3)=0,( n大于等于2,n属于N),则an=? 数列an,a1=1,n>=2,an=(根号下sn +根号sn-1)/2,求数列根号sn为等差数列,及an通项 数列an ,a1=1,当n>=2时,an=（根号sn+根号sn-1）/2,证明根号sn是等差数列,求an 数列an中a1=1,且对任意n皆有1/根号a1+1/根号a2+.+1/根号an=1/2根号an*an+1,求an通项公式 已知Sn是数列{An}的前n项和,A1=2,根号Sn—根号S(n-1)=根号2,求Sn的表达式 在数列an中,a1=1 a（n+1）*根号an=8求a2,a3设bn=log2 an ,求证 bn-2为等比数列求an的前n项积Tn