Difference between revisions of "Slope"

 
 
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The '''slope''' of a [[line]] can be intuitively defined as how steep the line is.  To be more precise, given two points <math>(x_1,y_1)</math> and <math>(x_2,y_2)</math> on a line, the slope is equal to  
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The '''slope''' of a [[line]] can be intuitively defined as how steep the line is, relative to some [[coordinate system]].  To be more precise, given a line <math>\mathcal L</math> in the [[Cartesian plane]] and two points, <math>(x_1,y_1)</math> and <math>(x_2,y_2)</math>, on <math>\mathcal L</math> with <math>x_1 \neq x_2</math>, the slope <math>m</math> of <math>\mathcal L</math> is equal to <math> \frac{y_1-y_2}{x_1-x_2}. </math>  If all points on <math>\mathcal L</math> have the same <math>x</math>-coordinate ([[abscissa]]), we say that <math>\mathcal L</math> has [[infinite]] slope.
  
<center><math> \frac{y_1-y_2}{x_1-x_2}. </math></center>
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Other expressions for the slope are
 
 
Other ways of expressing this are  
 
  
 
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|or <math>\frac{\rm{change \ in \ } y}{\rm{change \ in \ } x}</math>.
 
|or <math>\frac{\rm{change \ in \ } y}{\rm{change \ in \ } x}</math>.
 
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If <math>\theta</math> is the [[directed angle]] between the <math>x</math>-axis and <math>\mathcal L</math>, the slope is also given by <math>m = \tan \theta</math>.
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== See also ==
 
== See also ==
 
* [[Graphing]]
 
* [[Graphing]]
 
* [[Algebra]]
 
* [[Algebra]]

Latest revision as of 20:02, 29 September 2006

The slope of a line can be intuitively defined as how steep the line is, relative to some coordinate system. To be more precise, given a line $\mathcal L$ in the Cartesian plane and two points, $(x_1,y_1)$ and $(x_2,y_2)$, on $\mathcal L$ with $x_1 \neq x_2$, the slope $m$ of $\mathcal L$ is equal to $\frac{y_1-y_2}{x_1-x_2}.$ If all points on $\mathcal L$ have the same $x$-coordinate (abscissa), we say that $\mathcal L$ has infinite slope.

Other expressions for the slope are

$\frac{\rm{rise}}{\rm{run}},$
$\frac{\Delta y}{\Delta x}$ (read "delta $y$ over delta $x$"),
or $\frac{\rm{change \ in \ } y}{\rm{change \ in \ } x}$.


If $\theta$ is the directed angle between the $x$-axis and $\mathcal L$, the slope is also given by $m = \tan \theta$.


See also