Moore's 201 class at uvic? same boat...
the only useful thing I've written down is dT/dx = (1/2)(T)(N)
its dT/dx because its equal to the slope of the tangent line
Please post back with any progress you make and ill do the same
How much will a ray be "deviated"?
So my terrible phys prof presented this question but failed
to answer it and I have become very curious of the answer
after failing to answer it several times.
Here is a quick paint drawing of my question...