Interactive Unit Circle
The unit circle is where trigonometry lives: for an angle θ, the point on the circle is (cos θ, sin θ), and every identity follows from that picture. Drag the point around the circle and watch the sine and cosine segments change length, the tangent line grow toward infinity at 90°, and the sine wave unroll in real time alongside. Degrees and radians are shown together, with the standard angles marked, making this a reference tool for every trigonometry student.
Runs 100% in your browser — simulations are computed locally on your device.
Read the full guide to this tool
Notes
- cos θ and sin θ are just the x and y coordinates of the point at angle θ on the unit circle.
- tan θ is the length of the tangent segment — it blows up as θ approaches 90°, where cosine hits zero.
- One full turn is 2π radians = 360°; radians measure arc length along the unit circle.
- Runs 100% in your browser — simulations are computed locally on your device.
Related tools
3D Geometry Board
Points, lines, planes, spheres and polyhedra on an orbiting camera — slice solids with planes, unfold nets, drop the Dandelin spheres into a cone and drag everything.
Bézier Curve Playground
Drag control points and watch De Casteljau’s algorithm construct a Bézier curve step by step.
Central Limit Theorem Demo
Sample from any lopsided distribution and watch the averages pile up into a bell curve.
Conway’s Game of Life
Paint cells and watch Conway’s cellular automaton breed gliders, guns and oscillators.
Dynamic Geometry Board
Construct with points, lines, circles and transformations, then drag anything — the construction stays true, and a checker tells you which relations are theorems.
Fantasy Map Generator
Roll a seed and get a continent: coastlines, mountains, rivers, biomes and named towns, ready for your campaign.