Difference between revisions of "Perfect square"

m
Line 14: Line 14:
  
 
For any quadratic equation in the form <math>ax^2+bx+c</math>, it is a perfect square trinomial [[iff]] <math>b=a\sqrt{c}</math>.
 
For any quadratic equation in the form <math>ax^2+bx+c</math>, it is a perfect square trinomial [[iff]] <math>b=a\sqrt{c}</math>.
 
  
 
==See also ==
 
==See also ==
 
* [[Perfect cube]]
 
* [[Perfect cube]]
 
* [[Perfect power]]
 
* [[Perfect power]]
 +
 
{{stub}}
 
{{stub}}
 +
 +
[[Category:Definition]]

Revision as of 14:34, 19 April 2008

An integer $n$ is said to be a perfect square if there is an integer $m$ so that $m^2=n$. The first few perfect squares are 0, 1, 4, 9, 16, 25, 36.

The sum of the first $n$ square numbers (not including 0) is $\frac{n(n+1)(2n+1)}{6}$

An integer $n$ is a perfect square iff it is a quadratic residue modulo all but finitely primes.

Perfect Square Trinomials

Another type of perfect square is an equation that is a perfect square trinomial. Take for example

$(x+a)^2=x^2+2xa+a^2$.

Perfect square trinomials are a type of quadratic equation that have 3 terms and contain 1 unique root.

For any quadratic equation in the form $ax^2+bx+c$, it is a perfect square trinomial iff $b=a\sqrt{c}$.

See also

This article is a stub. Help us out by expanding it.