Why Sine and Cosine Always Equal One

追加: 2026-06-02

[00:00:00]Inside the unit circle, every point stays exactly one unit from the center.

[00:00:04]The radius creates two lengths. The horizontal length is cosine. The vertical length is sine.

[00:00:11]These lengths become the sides of two squares. The yellow square is built from cosine. The blue square is built from sine. As the angle rotates, one square grows while the other shrinks. But their combined area always stays equal to the same unit square. That is why sine squared plus cosine squared always equals one.

[00:00:32]A perfect geometric balance [music] hidden inside rotation.