Answer: (compiled from google)
One radian is the measure of the central angle of a circle such that the length of the arc is equal to the radius of the circle.
A full revolution of a circle ( 360 ∘ ) equals 2 π r a di a n s. This means that 1 radian = 180 ∘ π .
The formula used to convert between radians and degrees is angle in degrees = angle in radians ⋅ 180∘ π .
The radian measure of an angle is the ratio of the length of the arc to the radius of the circle ( θ = sr ) . In other words, if s is the length of an arc of a circle, and r is the radius of the circle, then the central angle containing that arc measures radians.
Key Terms
arc: A continuous part of the circumference of a circle.
circumference: The length of a line that bounds a circle.
radian: The standard unit used to measure angles in mathematics. The measure of a central angle of a circle that intercepts an arc equal in length to the radius of that circle.
The x – and y -coordinates at a point on the unit circle given by an angle
t are defined by the functions x = cos t and y = sin t .
Although the tangent function is not indicated by the unit circle, we can apply the formula
tan t = sin t cos t to find the tangent of any angle identified.
Using the unit circle, we are able to apply trigonometric functions to any angle, including those greater than 90 ∘ .
The unit circle demonstrates the periodicity of trigonometric functions by showing that they result in a repeated set of values at regular intervals.
Key Terms
periodicity: The quality of a function with a repeated set of values at regular intervals.
unit circle: A circle centered at the origin with radius 1.
quadrants: The four quarters of a coordinate plane, formed by the x – and y -axes.
If this doesn't help I appologize