Calculating Coterminal Angles in Radians: A Comprehensive Guide
TLDR; Determining coterminal angles in radians involves adding or subtracting multiples of 2/PI radians to a given angle. This process helps identify positive and negative coterminal angles with the same terminal side.
📐 Sketching the Angle
The angle in radians is sketched in a standard position, with the initial side and terminal side identified.
The angle of PI/3 radians is approximately equivalent to 60 degrees.
To determine another coterminal angle with the same terminal side, multiples of 2/PI radians are added or subtracted from the given angle in radians.
🔢 Calculating Coterminal Angles
To find another positive coterminal angle to PI/3 radians, 2/PI is added to the angle.
The resulting angle is calculated as 7PI/3 radians, representing the same terminal side as the initial angle.
For a negative coterminal angle, 2/PI radians are subtracted from the given angle, resulting in -5PI/3 radians.
🔄 General Rule for Coterminal Angles
The general rule for determining coterminal angles in radians involves adding or subtracting multiples of 2/PI x (K), where (K) is an integer.
Adding multiples of 2/PI results in positive coterminal angles, while subtracting multiples of 2/PI yields negative coterminal angles.
🔄 Handling Negative Angles
When dealing with negative angles in radians, the process of adding or subtracting multiples of 2/PI radians is still applied.
For example, to find a negative coterminal angle to -4PI/5 radians, multiples of 2/PI are added or subtracted accordingly.
📏 Finding Additional Coterminal Angles
By adding 10PI/5 radians to the given angle -4PI/5, the result is 6PI/5 radians, representing another negative coterminal angle.
Subtracting 10PI/5 radians from the given angle yields -14PI/5 radians, indicating another negative coterminal angle.