Setting up equation with variables without values

I am trying to set up in order to derive equations as I've been stuck on one thing for a few days now. One multiple sin or cos functions appear I simply don't know how to do them by hand.

I'm trying to set up an equation of

Thank you.

[Rik]

What did you try already? What are the constants? What are the variables? Which variable are you differentiating to?

[David Scidmore]

The best way to explain what I'm trying to do is find Xdot and Ydot for Laplace transformations. I want something I can come back to for quick solving of Laplace transformations when I'm working with Space State methodology.

Answer 1

[Asad (Mehrzad) Khoddam]

Use

(1/2)*Lp  % instead of 1/2Lp

[David Scidmore]

Thank you so much. Been working on this problem for a couple days so it's nice to be able to get to the point I finished in about 30 minutes.

I figured it was something really simple, but like python and arduino can't always tell while looking at your code.