Hey guys! I’m so sorry for the silly question but my math skills are very poor and I just need this problem fixed. I made a simple image about it and I hope it won’t confused you. In the image you can see 1. There is a Sphere with center point O 2. A cone which vertex is at O and radius is same as the sphere. The cone divides the sphere surface into two parts (red and blue) 3. the angle of the cone is α 4. Ray OC passes through the center of the base circle of the cone and intersects sphere surface at point C, which sphere coordinate is (θc, φc) 5. Point A (θa, φa) is a point on the sphere surface
The question is how to determine whether point A is in the red part of sphere surface according to its sphere coordinate(θa, φa)? Thank you very much!