Cos / Sin math help

I have two counters. Counter 1 always moves from 0 to 360, and then resets to 0 only to count back up to 360. This I have working fine.

Now I want to change counter 2 based on the value of counter 1. See the image below:
Please login to see this attachment.

Counter 2 should could down from 255, 254, 253 ... to 0, then up again to 255.

I tried asking chat gpt, and it gave me this formula which does not work:
Always set counter 2 to: 255 / 2 * ( 1 + Cos(3.14 * value( "counter 1" ) / 180) )

Second, I also want to try something similar, like this:
Please login to see this attachment.

Any ideas?

Thank you! That works perfectly.

Any idea how to do the second option?:

Please login to see this picture.

Thank you, but I didn't get that one to work as smoothly. I am attaching the mfa, frame 2 is showing that second option.

I should remove it?
If I do, the counter jumps on the transitions and the sky does not smoothly fade

Perfect, thank you!