what does the equal sign with an arrow mean?

Question

saifoo.khan · Answer

it mean 

less than & equal to
or
more than & equal to

anonymous · Answer

Does it depend on which side the arrow is on?

saifoo.khan · Answer

The "less than or equal to" sign:
≤
 	 
The "greater than or equal to" sign:
≥

saifoo.khan · Answer

the main thing depends upon it.

anonymous · Answer

$$<=$$  So this means less than or greater than?

anonymous · Answer

that means "implies", as in:
$$2x = 30 \Rightarrow x = 15$$

anonymous · Answer

in practice, most people just use it to go to the next step. So when someone reads a proof or a solution, they can have an easier time following it.

anonymous · Answer

Ok.  I am not sure as to the point, but that makes sense as to what it means.  While I have a smart person here, do you know what this means? Domain = (-1) $$\cup$$ (-1)

anonymous · Answer

More specifically, what does the $$\cup$$ mean?

myininaya · Answer

union

anonymous · Answer

Not really =/
The symbol:
$$\cup $$
is generally used with set notation and is called "union"

anonymous · Answer

ignore the "not really" comment <.<

myininaya · Answer

if your solution or domain is disjoint they put this U symbol and there like we do with conjunctions in english to say and or or

anonymous · Answer

Thank you guys so very much!!  We greatly appreciate it!!  Hope ya'll have a great day and may GOD bless<><

anonymous · Answer

answer my problem myininaya :P http://openstudy.com/users/joemath314159#/users/joemath314159/updates/4e10ebfb0b8b56e55598a160

myininaya · Answer

U means kindof like or
n means kindof like and

anonymous · Answer

That is very helpful!!  THANK YOU SO MUCH!!  God bless<><