伝達関数の記述方法

初歩的な質問で恐縮ですが，下記のような伝達関数をmatlabで表現することは可能でしょうか？

P(s) = K/(cosh(sqrt((a/b)*s)))

[Dyuman Joshi]

You can not use a transfer function to define a non-linear system, it is limited to linear systems only.

How do you plan to use the function?

[貴弘]

Thank you for your answer!

This function is transfer function of heat diffusion equation.

I try to calculate it using the differential equation of the heat diffusion equation.

[Dyuman Joshi]

So you want to solve a differential equation? Are you going to implement an ode solver for that?