Neil
1. “The great circle bearing of position B from position A in the northern hemisphere is 040 degrees. If Conversion Angle is 4 degrees, what is the great circle bearing of A from B?”
If the GC bearing from A to B is 040, and the CA is 4, the RL bearing A to B is 044. As the RL direction is constant, the RL bearing from B to A is the reciprocal of 044, that is 224. To find the GC bearing B to A apply CA again, that is 224 + 4 = 228. A sketch (best drawn with the GC as a straight line as Sinbad suggests) should help decide the ‘plus or minus’ question:
2. “The great circle bearing from A (70S 030W) to B (70S 060E) is approximately?”
As the two points are at the same latitude and B is East of A, the RL bearing A to B must be 090. The CA is ˝ chlong x sin lat = 42. The GC bearing is thus 090 ± 42. Again, a sketch will resolve the ‘plus or minus’ question – in this case it is +, so the answer is 132. I suspect you might not have drawn a southern hemisphere diagram.
PM me with your e-mail address if you want more.
Bob