Positive and Negative Coterminal Angles

The coterminal angles can be positive or negative. In one of the above examples, we found that 390° and -690° are the coterminal angles of 30°

Here,

• 390° is the positive coterminal angle of 30° and
• -690° is the negative coterminal angle of 30°

θ ± 360 n, where n takes a positive value when the rotation is anticlockwise and takes a negative value when the rotation is clockwise. So we decide whether to add or subtract multiples of 360° (or 2π) to get positive or negative coterminal angles.