Analyze amplitude, period, phase shift, and vertical shift of trig functions.
The general sinusoidal function y = A sin(B(x − C)) + D has amplitude |A|, period 2π/|B|, phase shift C, and vertical shift D. Understanding these parameters lets you graph any sinusoidal function quickly.
Key Properties
A = 3 → amplitude 3. B = 2 → period = 2π/2 = π. Phase shift = π/4 (right). D = 1 → midline y = 1. Maximum value: 1 + 3 = 4. Minimum: 1 − 3 = −2.
Remember This!
For cosine, y = A cos(B(x − C)) + D. Cosine starts at the maximum when x = C (where the phase shift brings you to x = 0 of the base function). Sine starts at the midline.
What is the period of y = sin(4x)?