wolframalpha is your friend. See
http://www.wolframalpha.com/input/?i=3cos+(4pix+-pi%2F2)+-2
f(x) = 3cos(4pi(x - 1/8) -2
So, it is just the graph of cos(x)
shrunk horizontally by a factor of 4pi
shifted right by 1/8
stretched vertically by 3
shifted down 2
Graph f (x) = 3cos (4pix -pi/2) -2
2 answers
Thank you