Resol a_{n}=(n+1)^2

$$a _ { n } = ( n + 1 ) ^ { 2 }$$

Resoleu a_n

$$a_{n}=\left(n+1\right)^{2}$$

Passos de solució

Utilitzeu el teorema del binomi \left(a+b\right)^{2}=a^{2}+2ab+b^{2} per desenvolupar \left(n+1\right)^{2}.

$$a_{n}=n^{2}+2n+1$$

Resoleu n (complex solution)

$$n=-\left(\sqrt{a_{n}}+1\right)$$

$$n=\sqrt{a_{n}}-1$$

Resoleu n

$$n=-\left(\sqrt{a_{n}}+1\right)$$

$$n=\sqrt{a_{n}}-1\text{, }a_{n}\geq 0$$