How do you write an equation of a cosine function with Amplitude=2.4, Period=0.2, Phase Shift=pi/3, and Vertical shift=.2?

1 Answer
Mar 30, 2018

y=12/5cos(10pix-(10pi^2)/3)+1/5y=125cos(10πx10π23)+15

Explanation:

Trigonometric functions can be expressed in the form:

y=acos(bx+c)+dy=acos(bx+c)+d

Where:

\ \ \bba \ \ \ \ \ \ \ \ is the amplitude.

bb((2pi)/b) \ \ \ \ \ \ is the period. *

bb((-c)/b) \ \ \ \ \ \ is the phase shift.

\ \ \ bbd \ \ \ \ \ \ \ \ is the vertical shift.

(where 2pi is the normal period of the cosine function ) *

We require:

a=2.4=12/5

Period of 0.2=1/5

:.

(2pi)/b=1/5

b=10pi

Phase shift of pi/3

(-c)/(10pi)=pi/3

c=-(10pi^2)/3

Vertical shift of 0.2=1/5

d=1/5

:.

y=12/5cos(10pix-(10pi^2)/3)+1/5