Expression: $\lim_{n \rightarrow +\infty} \left(\frac{ \sqrt{ n-1 } }{ \sqrt{ n+1 } } \times 1\right)$
Use $\lim_{x \rightarrow c} \left(a \times f\left( x \right)\right)=a \times \lim_{x \rightarrow c} \left(f\left( x \right)\right)$ to transform the expression $1 \times \lim_{n \rightarrow +\infty} \left(\frac{ \sqrt{ n-1 } }{ \sqrt{ n+1 } }\right)$
Evaluate the limit $1 \times 1$
Any expression multiplied by $1$ remains the same $1$