@C_R A smart direction to substitute the angles which could also work. It turned out, as you also said, that Maple assumes radians. I almost always use a general package except for this time, where I found it changes the default to degrees instead of radians and thus it did not occur to me at first glance.
But thank you very much for all the effort you put into the answer, I greatly appreciate someone taking time out of their day to help, even though it was a dumb mistake on my part :)

Best regards

Jakob

It was just a dumb mistake. I found an old post in here that says Maple assumes radians and not degrees for trigonometric functions. Using both the convert(cos(x),radians) function and (cos(x*pi/180)) gives a reasonable answer and also the same answer for both.

Thank you all for you time :)

- Jakob