Unit Circle Navigator – AP Precalculus

Learning Objectives

Evaluate sine, cosine, tangent from unit circle coordinates

Convert between degrees and radians

Identify reference angles and quadrant signs

Memorize key angles: 0°, 30°, 45°, 60°, 90° and multiples

Key Relationships

\(\cos\theta = x\)-coordinate
\(\sin\theta = y\)-coordinate
\(\tan\theta = \sin\theta / \cos\theta\)
\(\sin^2\theta + \cos^2\theta = 1\)

Quadrant Signs

I: All + · II: Sin +
III: Tan + · IV: Cos +
Mnemonic: All Students Take Calculus