Unit circle

The unit circle is the circle around the origin of a coordinate system with radius $r = 1$ .

The unit circle is the circle around the origin of a coordinate system with radius $r = 1$ . This means it represents the set of all points that have a distance of $1$ from the origin.

For example, the points

$(1 | 0)$
$(0 | 1)$
$(- 1 | 0)$
$(0 | - 1)$

are on the unit circle.

Application

The unit circle can be used to illustrate the trigonometric functions sine, cosine and tangent. See the related article: Trigonometry on the unit circle

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