Question

what kind of function is this? i'm not sure what the notation means: y=[[2x]]

Answer 1

[[ ]] <---- floor function


[[ 3.5 ]] = 3

[[ -3.5 ]] = -4

Answer 2

http://mathworld.wolfram.com/FloorFunction.html

Answer 3

why [[-3.5]]=-4? why double [[]] ?

Answer 4

I gather some material uses the single bracket, the ones I've read it one, use the double bracket

Answer 5

-4 is the smallest integer it can round up to , -4 is smaller then -3

Answer 6

thanks!
also, would this be considered a one-to-one function?

Answer 7

ok, I got why [[-3.5]]=-4

Answer 8

Thanks @jdoe0001

Answer 9

yw

Answer 10

it is not one-to-one (doesn't pass the horizontal line test)