(adsbygoogle = window.adsbygoogle || []).push({}); I confronted "something" in math which is way too confusing to me !!

Hello forums ,

I am currently in class 10th , and 15 years... I was doing Khan Academy Pre-calculus yesterday and I confronted something too weird ... not weird though but way too confusing...

Here is the link :

http://www.khanacademy.org/video/more-limits?playlist=Precalculus [Broken]

Now what I am confused with , is that , Sal ( That's not a name of a tree !) says that

lim(x-2|x|)/|x|

x→0

Then he says that when limit x tends to 0 from positive side then :

lim(x-2|x|)/|x|

x→0^{+}

is SAME AS

lim(x-2x)/x

x→0^{+}

which is equal to

lim(x-2|x|)/|x| = -1

x→0^{+}

This makes sense to me and here comes which confuses me :

Now Sal says that when x approaches 0 from negative side then :

lim(x-2|x|)/|x|

x→0^{-}

is SAME AS

lim(x-2(-x))/-x

x→0^{-}

which is equal to

lim(3x)/-x

x→0^{-}

SO

lim(x-2|x|)/|x| = -3

x→0^{-}

This does not make sense ! |-x| → |x| right ?

Why he wrote |-x| = -x ?! OR |x| = -x ? ! where x < 0 ?!

Can someone explain it to me , please ?

Thanks in advance ...

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# I confronted something in math which is way too confusing to me

**Physics Forums | Science Articles, Homework Help, Discussion**