Understanding Algebraic Variables with a Dash: Help with Math Term Explanation

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In summary, an algebraic variable with a dash above it can have different meanings depending on the context. It can be used as a decoration to create a new symbol, denote the complex conjugate function, or represent equivalence classes. In the case of complex numbers, the dash above a variable indicates the complex conjugate, which can be used to find the absolute value of the number.
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Ghost803
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What does it mean when an algebraic variable has a dash above it? _
---------------------------------------------------------------->z, like that?
 
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  • #2
Ghost803 said:
What does it mean when an algebraic variable has a dash above it? _
---------------------------------------------------------------->z, like that?
Sometimes it's just used as a decoration to create a new alphabetic symbol to use. (there aren't enough alphabets for the purposes of mathematics!)

Sometimes it's used to denote the complex conjugate function: [tex]\overline{a + bi} = a - bi[/tex].

Sometimes it's used to denote equivalence classes; e.g. when it's evident you're working modulo 3, the relation [itex]2 \equiv 5 \pmod 3[/itex] can be expressed as [itex]\bar{2} = \bar{5}[/itex].
 
  • #3
If you want fixed width fonts, then you need to put in some tags. I think it might be 'code'. Otherwise attempting justification doesn't work since it is font specific, or machine dependent.

Code:
  _
  z
 
  • #4
[tex]\overline{z}[/tex]
 
  • #5
it says the absolute value of z equals the absolute value of [tex]\overline{z}[/tex]. This was in a list of properties of absolute value.
 
  • #6
Okay, then you are talking about complex numbers and the "overline" denotes the complex conjugate

If z is a complex number, say z= a+ bi, so its absolute value is [itex]|z|= \sqrt{a^2+ b^2}[/itex]. As Hurkyl said, then, [itex]\overline{z}= a- bi[/itex] so that its absolute value is [itex]|\overline{z}|= \sqrt{a^2+ (-b)^2}= \sqrt{a^2+ b^2}= |z|[/itex].

One can also define absolute value of a complex number by [itex]|z|= \sqrt{z\overline{z}}[/itex].
 
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  • #7
Thx a lot. Makes sense now.
 

FAQ: Understanding Algebraic Variables with a Dash: Help with Math Term Explanation

What is a Math term?

A Math term is a word or phrase that has a specific meaning or definition in the field of mathematics. It is used to describe a mathematical concept, process, or idea.

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