\[\mathop {\lim }\limits_{x \to + \infty } \left( {\frac{{\cosh \left( {nx} \right)}}{{{{\cosh }^n}x}}} \right)\]

\[\mathop {\lim }\limits_{x \to 0} \left( {\frac{{{{\left( {1 + x} \right)}^m} - {{\left( {1 - x} \right)}^m}}}{{{{\left( {1 + x} \right)}^n} - {{\left( {1 - x} \right)}^n}}}} \right)\]