it is the point at infinity where it is at a distance from the curve equal to the radius of curvature lying on the normal vector. Sorry no diagram
Define unit vectors as follows:

is in the eastern direction.

is in the northern direction.
The position of the first bird is

The position of the second bird is

Let θ = the angle between the net displacement vector for the two birds.
By definition,



Similarly,
|b| = 4.025
Therefore

Answer: 36.9°
I have all the answers here so take this