
Bradford T. answered 03/19/21
MS in Electrical Engineering with 40+ years as an Engineer
Model for secant is:
Asec(B(x+C)) + D , A= Amplitude, B= 2π/period, C = left phase shift and D = vertical shift
Normally the range for secant is y ≤ -1 or y ≥ 1, so A = 2 to match the criteria. D=0 and C=0.
B = 2π/3π = 2/3
y = 2sec(2x/3)