Identifying equivalence classes with the unit circle

In summary, the unit circle is a useful tool for identifying equivalence classes based on the angle formed between the positive x-axis and a point on the circle. This allows us to group points with similar properties and understand their relationships. The points on the unit circle are also closely related to the trigonometric functions, with the x-coordinate representing the cosine and the y-coordinate representing the sine of the angle. Quadrantal angles, which have their terminal side on one of the axes, have special properties that can be helpful in solving trigonometric equations. Finally, radians can be used to measure the arc length on the unit circle and correspond to specific equivalence classes.
  • #1
The1TL
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Homework Statement



Define a relation on R as follows. For a,b ∈ R, a ∼ b if a−b ∈ Z. Prove that this is an equivalence relation. Can you identify the set of equivalence classes with the unit circle in a natural way?

Homework Equations


The Attempt at a Solution



I have already proven that this is an equivalence relation but i do not understand how the equivalence classes relate to the unit circle
 
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  • #2
One fairly obvious equivalence relation on the unit circle can be obtained by considering the results of using θ and (2π + θ) as arguments of the trig functions.
 

Related to Identifying equivalence classes with the unit circle

1. How do you identify equivalence classes with the unit circle?

The equivalence classes on the unit circle are determined by the angle between the positive x-axis and the point on the circle. Each angle corresponds to a unique equivalence class.

2. What is the purpose of identifying equivalence classes with the unit circle?

Identifying equivalence classes on the unit circle allows us to group points with similar properties and understand their relationships and patterns.

3. How are the points on the unit circle related to the trigonometric functions?

The x-coordinate of a point on the unit circle is equal to the cosine of the angle formed by the point and the positive x-axis, while the y-coordinate is equal to the sine of the angle. This relationship allows us to use the unit circle to evaluate trigonometric functions.

4. Can you explain the concept of quadrantal angles on the unit circle?

Quadrantal angles are angles that have their terminal side on one of the axes of the unit circle. These angles have special properties, such as having a cosine or sine value of 0, which can be useful in solving trigonometric equations.

5. How does identifying equivalence classes on the unit circle relate to radians?

Radians are a unit of measurement for angles, and they can be used to identify equivalence classes on the unit circle. Each equivalence class corresponds to a specific angle in radians, which can be used to measure the arc length on the unit circle.

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