# Sat Practice Help

• Jan 28th 2007, 07:13 AM
Mr_Green
Sat Practice Help
Hello! I bought an SAT practice book to get ready for the big test. It is pretty well formated, except it only has the answers/explanations to random questions. I was just hoping that you guys could help me with a question here or there that I didn't know how to solve. Thanks!

Find the set of all real x where 0 < x < 2pi, such that cos(2x) > 0
• Jan 28th 2007, 07:38 AM
ThePerfectHacker
Quote:

Originally Posted by Mr_Green
Find the set of all real x where 0 < x < 2pi, such that cos(2x) > 0

I hope you know how the cosine curve looks like, (see below), you are expected to graph it by hand.

In that case the answer is simple.
Graph $y=\cos 2x$ an observe.

To get,
$0
$3\pi/4
$7\pi/4
• Jan 28th 2007, 07:50 AM
Mr_Green
.....
Ok. thanks! I understand what the questions wanted know!