Redbull's Question Thread

[red bull]

Hi all! i am having some difficulty with modulus can u please help me and fully explain each step on how u get the answer. Here are my questions:

1. on a number line, illustrate each of the following sets and represent the sets using interval notation.

a) {x:|x|<3}
b) {x:|x|≥5}
c) {x:|x-2|≤1}

[TrueTears]

Try split it up into cases.

Eg, if

if

[red bull]

i still don't get it...

[TrueTears]

Well that's the definition of a modulus function. You can read more about in the Essentials textbook (do you use it?)

[kamil9876]

I think if a graph is supposed to be drawn, might as well use the definition "|a| is the distance between 0 and a on the number line"

[superflya]

I love u modulus :p

[Ilovemathsmeth]

Modulus function is most easily understood if you separate the function into its different sections and give them rules.

First consider the function within the modulus. Where is it positive? Where is it negative?

For the positive parts, the original function will hold, i.e. you just need to remove the modulus sign from the function given.

For the negative parts, you need to negate the original function (apply neg sign once modulus is taken away) as you are reflecting it in the x-axis to make those y-values positive.

Then you've got your rules - it's easier to do anything with modulus functions now.