Thanks for your patiance with me :) Your help is highly apperciated.
This is a bit awkward and im not proud to do so.
i´m not the guy to get anyone doing my homework but at this stage I feel like I have to reach out for help since I cannot get the problem right.
I have tried an different approach that gave a good representation of the area im after, but just an good approximation and as we are heading towards the finals I have spent significant amount of time trying to get it right but so far i had no luck.
The problem is like this:
A circular beam of light with radius of 20mm (circular with no spreads) shines perpendicular on to a tank with radius of 40, calculate the area on the tank covered by light.
What I did to solve this problem was sketching an ellipse with the big radius on the x-axsis=the 2arc length of the tank/2 and the little radius=the radius of the beam.
The resultant answear was 1315 while the actual answere should be 1300.xx
Do you think there is any chance you can help me set up the surface integral for that specific case?