Cusa-Huygens type inequality and a correction for generalized trigonometric functions

In this paper, we mainly give several Cusa-Huygens and Kober type inequalities for generalized trigonometric functions by using classical analysis. Finally, we also show that the proof of Theorem 3.9 given by Huang et.al. in the paper "Some Wilker and Cusa-Huygens type inequality for generalized trigonometric functions" is incorrect. In addition, we present a weak result by using l'Hospital monotone rule.