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What is Unit Circle?

The unit circle definition of sine, cosine, & tangent

Unit Circle:

A unit circle intends a circle with a radius of 1 unit.
It is an excellent idea to understand and communicate regarding lengths and trigonometric functions.

In the fig. where the x-axis and y-axis cross, so we can calculate the neat arrangement here.

Unit Circle Trigonometry

Sine, Cosine and Tangent

The trig functions & right triangle trig ratios

As we know the radius of the circle is 1, then we can immediately calculate sine, cosine, and tangent.

 sine, cosine and tangent

Trig unit circle review What happens when we put the angle, θ, is 0°?

cos 0° = 1,

sin 0° = 0

and tan 0° = 0


What happens when we put the angle, θ, is 90°?angle90

cos 90° = 0,

sin 90° = 1

and tan 90° = undefined