# Graphing trig functions

1. May 26, 2005

### dash00

i have a problem graphing trig functions such as f(x) = 2cos(3x+pi/2) -1

i know this should be very simple but i am missing something

can someone explain the way youd go about graphing this
amp= 2
period = 2pi/3
y trans = -1
x trans = (pi/2)/3 [right?]

so when i try graph it my answer is wrong, what am i missing? is it something to do with the smaller period, need help , please!

2. May 26, 2005

### dextercioby

HINT:$$\cos \left(3x+\frac{\pi}{2}\right)=-\sin 3x$$

Daniel.