What's the meaning of this symbol?

[Asuralm]

Dear All:

What's the meaning of a equal sign with a triangle over it please?

Thanks in advance

 

[HallsofIvy]

I will confess that I did not recognize that immediately but according to Wikipedia:
http://en.wikipedia.org/wiki/Table_of_mathematical_symbols
(down near the bottom of the page) it means "is defined as" or "is equal by definition".
After seeing that definition, my reaction was, "Oh, yes, of course, I've seen that before".
Different authors use different symbols for that.

 

[ben5777]

Dear All

what is the meaning of these symbols =,<>,!=,>,<,!<,<=,!>

 

[HallsofIvy]

= means "is equal to"
> means "is greater than"
< means "is less than"
<> means "is either less than or greater than" or simply "is not equal to"

! is a commonly used to mean "not"
!= means "is not equal to"
!> means "is not greater than"
!< means "is not less than"