Unit Circle 5: Coterminal and Reference Angles

Front

What are coterminal angles?

Back

Coterminal angles are angles that share the same terminal side when drawn in standard position. They can be found by adding or subtracting multiples of 360°.

Front

How do you find a positive coterminal angle for a given angle?

Back

To find a positive coterminal angle, add 360° to the given angle until the result is positive.

Front

How do you find a negative coterminal angle for a given angle?

Back

To find a negative coterminal angle, subtract 360° from the given angle until the result is negative.

Front

What is a reference angle?

Back

A reference angle is the acute angle formed by the terminal side of an angle and the x-axis. It is always positive and less than 90°.

Front

How do you calculate the reference angle for angles in Quadrant II?

Back

For angles in Quadrant II, subtract the angle from 180° to find the reference angle.

Front

How do you calculate the reference angle for angles in Quadrant III?

Back

For angles in Quadrant III, subtract 180° from the angle to find the reference angle.

Front

How do you calculate the reference angle for angles in Quadrant IV?

Back

For angles in Quadrant IV, subtract the angle from 360° to find the reference angle.

Front

Which trigonometric functions are positive in Quadrant I?

Back

In Quadrant I, all trigonometric functions (sine, cosine, tangent, secant, cosecant, and cotangent) are positive.

Front

Which trigonometric functions are positive in Quadrant II?

Back

In Quadrant II, sine and cosecant are positive; cosine, tangent, secant, and cotangent are negative.

Front

Which trigonometric functions are positive in Quadrant III?

Back

In Quadrant III, tangent and cotangent are positive; sine, cosine, secant, and cosecant are negative.