Question

How do you use transformation to graph the cosine function and determine the amplitude and period of `y=cos(-1/4x)`?

Answer 1

As below

Explanation:

Standard form of a cosine function is `y = A cos (Bx - C) + D`

`"Given : " y = cos (-x/4)`

`A = 1, B = -(1/4), C = D = 0`

`"Amplitude ' = |A| = 1`

`"Period " = (2 pi) / |B| = (2 pi) / |-1/4| = 8 pi`

`"Phase Shift " = -C / B = 0`

`"Vertical Shift " = D = 0`

![https://www.symbolab.com/solver/function-periodicity-calculator/periodicity%20f%5Cleft(x%5Cright)%3Dcos%20%5Cleft(-%5Cfrac%7Bx%7D%7B4%7D%5Cright)]()