Radian Peak Angles

Turn one point around the unit circle and watch sine, cosine and tangent become lengths you can see.

Radian Peak Angles is a hands-on trigonometry companion. Instead of memorising a table, you drag an angle and watch every value move with it.

THE UNIT CIRCLE
- Drag a point around the unit circle; sine and cosine are drawn as teal and amber lengths.
- Tangent appears where the extended radius meets the tangent line x = 1.
- Reference angle and quadrant signs are highlighted live.
- The Pythagorean identity sin² + cos² = 1 is shown as a shaded right triangle with exact squares.

GRAPHS
- Sine and cosine waves unroll from 0 up to the current angle beside the circle.
- Full graphs of sine, cosine and tangent with a shared cursor.
- Inverse functions are graphed with their principal ranges shown as a coral band.

EXACT VALUES
- Snap lands on the 16 special angles and shows their exact surd values.
- Exact values for every special angle, with reference angles and signs by quadrant.
- Work in degrees or radians.

QUIZ
- Quiz yourself on exact values, signs, reference angles, radians and inverses.
- Build streaks as you answer correctly.

A "How" tab explains each idea in plain steps.

QUIET AND PRIVATE
Radian Peak Angles works fully offline and needs no internet connection. There are no ads, no sound and no sign-in. Your progress stays on your device.