Câu 14:
Tìm limun\lim {u_n}limunbiết un=n.1+3+5+...+(2n−1)2n2+1{u_n} = \dfrac{{n.\sqrt {1 + 3 + 5 + ... + (2n - 1)} }}{{2{n^2} + 1}}un=2n2+1n.1+3+5+...+(2n−1)
