Question

Greatest Integer Function help !

Choose the best graph to match the given expression.

f(x) = [2x]

I have no idea how to do this. I read, re-read, and re-read my lesson once more. I have gathered nada from it. I even looked up videos on how to do it, but it doesn't make sense to me. Can someone please help ? Thanks so much! I really appreciate it :) I know how to graph it on my calculator, but I would like to understand what I am doing. (:

Answer 1

For all real numbers x, the greatest integer function returns the largest integer less than or equal to x.

pick some numbers for x: let's try 0, 0.25, 0.5, 0.9, 1, 1.25
x 2x [2x]
0 0 0
.25 0.5 0
0.5 1 1
0.9 1.8 1
1 2 2
1.25 2.5 2

it looks like you get a horizontal line at y=0 for x=0 upto 0.49999
then it jumps to y=1 at x= 0.5 to 0.99999

Is that enough info to pick the correct graph?

Answer 2

I mean, I understand how to get your numbers to graph it, but to actually graph it boggles me. Does that make sense?

Answer 3

& thanks for helping!

Answer 4

This explains how to plot points
http://www.khanacademy.org/math/algebra/linear-equations-and-inequalitie/v/the-coordinate-plane

Answer 5

The part that confused me is when it has to go diagonal or up or curved or what not.. Like I know how to plot a point. I don't think I'm conveying what I'm trying to say..

Answer 6

if you plot enough points and they are close enough together, you just connect the dots

that works here
(see http://www.wolframalpha.com/input/?i=Greatest+Integer+Function+)
until you get to a "jump"

Answer 7

Okay thanks, I'll study that like there is no tomorrow! I really appreciate it !!!! (: