Sine from Circle Lab
Unwrap the unit circle into a sine wave. A point travels the circle while a sine wave from the unit circle draws the same height — y = sin θ — against the angle. Play, pause, or drag. Turn on cosine for an interactive sine cosine circle, the picture of unwrapping the unit circle. Free, no login, ready for a classroom projector.
Who·Algebra 2 and precalculus on a projector or iPad
Teacher tip
Project this page and tap Full screen. It opens at 0°. Tap Play and watch one turn: the point's height on the circle is the height of the sine wave. Pause near the top — about 90°, sine 1 — then drag a point on the wave back toward 180° and the circle follows. Tap Cosine and play again: the blue wave is the horizontal coordinate, cosine. Slow gives the room a longer look. For one angle and its right triangle, open the Unit Circle Lab.
Play, or drag the point. The height on the circle is the height on the wave.
Degrees
0°
Radians
0
sin θ
0
0 degrees, 0 radians. Sine 0.
Drag the circle or the wave. Arrows move one degree. Shift plus an arrow moves 15°. Space plays and pauses while the picture is focused. Escape clears. The right triangle for one angle is in the Unit Circle Lab.