A generalization of L’Hôspital-type rules for monotonicity and its application

This paper deals with a generalization of L’Hôspital-type rules for monotonicity. The result is then used to establish a class of two-sided bounding inequalities for higher-order differentiable functions. As consequences, some refined upper and lower bounds for exponential function, logarithmic function, trigonometric functions and hyperbolic functions are derived.