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

1 Answer
Feb 23, 2018

One of the standard forms of a trig function is y = ACos(Bx + C) + D

Explanation:

A is the amplitude (absolute value since it's a distance)

B affects the period via formula Period = {2\pi}/B

C is the phase shift

D is the vertical shift

In your case, A = -1, B = 1, C = -\pi/4 D = 0

So, your amplitude is 1

Period = {2\pi}/B->{2\pi}/1->2\pi

Phase shift = \pi/4 to the RIGHT (not the left as you might think)

Vertical shift = 0