如何证明3n+2/2n+1的极限等于3/2
问题描述：
如何证明3n+2/2n+1的极限等于3/2
n趋近于无穷大
答
lim(3n+2)/(2n+1)
=lim[(3n+3/2)/2*(n+1/2) +1/2*(2n+1)]
=lim[3/2+1/(4n+2)]
=3/2+lim[1/(4n+2)]
n趋近于无穷大,lim[1/(4n+2)]=0
所以：n趋近于无穷大
lim(3n+2)/(2n+1)＝3/2
或者：
lim (3n+2)/(2n+1)
=lim[(3+2/n)/(2+1/n)]
n趋近于无穷大 2/n和1/n均趋向于0
所以：
n趋近于无穷大
lim (3n+2)/(2n+1)
=lim[(3+2/n)/(2+1/n)]＝3/2