Lesson 2: Power Functions Any function that can be written in the form where k and a are nonzero function. The constant is the power, and is the constants, is a , or constant of We say constant of f(x) varies as the ath power of x, or f (x)is to the ath power of x. Common Formulas from Geometry and Science Name Formula Power Constant of Variation Circumference C = 2nr Area of a circle A = mr2 Force of Gravity k F = Boyle's Law k V = p Writing and Analyzing Power Functions EX #1: In the formula d = gt2 , state the power and the constant of variation. Power: Constant of Variation: EX #2: Write the statement as a power function, use k as the constant of variation. "The area A of an equilateral triangle varies directly as the square of the length s of its sides." EX#3: State the power and constant of variation for the function below, graph it, and analyze it. f (x) = 2Vx