Difference between revisions of "Discriminant"

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The '''discriminant''' of a [[Quadratic Equations | Quadratic Equation]] of the form  
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The '''discriminant''' of a [[Quadratic Equations | Quadratic Equation]] of the form <math>a{x}^2+b{x}+{c}=0</math> is the quantity <math>b^2-4ac</math>.  When <math>{a},{b},{c}</math> are real, this is a notable quantity, because if the discriminant is positive, the equation has two [[real]] [[Roots | roots]]; if the discriminant is negative, the equation has two [[nonreal]] roots; and if the discriminant is 0, the equation has a [[real]] [[Double Root | double root]].
 
 
<math>a{x}^2+b{x}+{c}=0</math>  
 
 
 
is the quantity <math>b^2-4ac</math>.  When <math>{a}</math>, <math>{b}</math>, and <math>{c}</math> are real, this is a notable quantity, because if the Discriminant is positive, the equation has two real [[Roots | roots]]; if the discriminant is negative, the equation has two non-real roots; and if the discriminant is 0, the equation has a real [[Double Root | double root]].
 
  
  
 
== Other resources ==
 
== Other resources ==
 
* [http://en.wikipedia.org/wiki/Discriminant Wikipedia entry]
 
* [http://en.wikipedia.org/wiki/Discriminant Wikipedia entry]

Revision as of 09:01, 18 June 2006

The discriminant of a Quadratic Equation of the form $a{x}^2+b{x}+{c}=0$ is the quantity $b^2-4ac$. When ${a},{b},{c}$ are real, this is a notable quantity, because if the discriminant is positive, the equation has two real roots; if the discriminant is negative, the equation has two nonreal roots; and if the discriminant is 0, the equation has a real double root.


Other resources