# 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 =

C is the phase shift

D is the vertical shift

In your case, A = -1, B = 1, C =

So, your amplitude is 1

Period =

Phase shift =

Vertical shift = 0