Optimal evaluations of some Seiffert-type means by power means

Let us consider the second trigonometric mean T defined by Seiffert and the hyperbolic mean M defined by Neuman and Sandor. There are some known inequalities between these means and some power means A"p. We prove that the evaluationsA"l"n"2"/"l"n"("l"n"("3"+"2"2")")