What is a co-terminal?

Answer 1

Co-terminal angles are angles that share the same terminal side when drawn in standard position, differing only by an integer multiple of 360 degrees (or 2π radians). For example, 30 degrees and 390 degrees are co-terminal because if you add 360 degrees to 30, you arrive at 390. This concept is useful in trigonometry, as it allows for simplification of angle measurements and calculations. In essence, co-terminal angles represent the same direction or position on the unit circle.