The Pre-Calculus course in Loudoun County is really a combination of Trigonometry and College Algebra.  Algebra II skills are critical - especially factoring, graphing, and solving quadratics.  Brand new material is introduced in Pre-Calculus during the Trigonometry instruction.  Heavy emphasis is placed on the unit circle, trigonometric identities, and solving trigonometric equations.  Logarithms and exponential functions are also heavily emphasized.