Functions / Trigonometry

Circular Functions and Transformations

Use the unit circle to understand sine, cosine and tangent graphs, then transform them.

Unit-circle definitions

For an angle \(\theta\), the point on the unit circle has coordinates

\[(\cos\theta,\sin\theta).\]
(cosθ, sinθ)cosθsinθ
On the unit circle, the point at angle \(\theta\) has coordinates \((\cos\theta,\sin\theta)\).

Graph transformations

For a function such as

\[y=a\sin(b(x-c))+d,\]