How do you find the amplitude, period, and phase shift of 4cos(3θ+32π)+2?

1 Answer
Jun 4, 2015

First, the range of the cosinus function is [-1;1]
therefore the range of 4cos(X) is [-4;4]
and the range of 4cos(X)+2 is [-2;6]

Second, the period P of the cosinus function is defined as: cos(X)=cos(X+P) P=2π.
therefore:

(3θ2+32π)(3θ1+32π)=3(θ2θ1)=2π

the period of 4cos(3θ+32π)+2 is 23π

Third, cos(X)=1 if X=0
here X=3(θ+π2)
therefore X=0 if θ=π2
therefore the phase shift is π2