Unit Circle & Trig Explorer
Drag around the unit circle and watch sine, cosine and tangent trace their waves.
Angle (degrees)0°
Angle (radians)0
cos θ1
sin θ0
tan θ0
Quadrant–
What you can learn
- On the unit circle a point at angle θ has coordinates (cos θ, sin θ).
- Radians measure the arc length: 180° = π radians.
- Unrolling the circle over time gives the sine and cosine waves.
Frequently asked questions
How do I convert degrees to radians?
Multiply by π / 180. For example 90° = π/2 radians and 180° = π radians.
Why is tan undefined at 90 degrees?
Tangent is sin ÷ cos, and cos 90° = 0, so you would divide by zero.