Denise G. answered 04/21/20
Algebra, College Algebra, Prealgebra, Precalculus, GED, ASVAB Tutor
The cos functions is in this form: f(x) = A cos B(x + C) + D
A is the amplitude
2π/B is the period
C is the horizontal shift
D is the vertical shift
We can take each piece of what is given and plug it into the equation.
Since the diameter = 220, the amplitude will be half of that, 110=A
The Ferris wheel has a period of 2 minutes, the time it takes to make one full revolution.
2π/B=2
B=π
The center is 125 ft off the ground, the is the vertical shift.
D=125
The are telling you that the Ferris wheel is at the lowest point when t=0. Normally the parent function shows cos at the highest point. This can be accomplished one of 2 ways.
Option 1 is add a negative sign and have it reflect on the x axis.
f(x) = -110 cos (πx) + 125
Option 2 is you can also add a phase shift of half the period to the left. Half the period is 1.
f(x) = 110 cos π(x + 1) + 125