Angles and graphs, basic question

[darkelf]

Hi,

Is there a way of calulating the angles from the slope or coordinates of a graph. Say you have a bunch of x and y coordinates and you want to find the angles between those points at various coordinates (say every x,y ratio) can it be done?
How would you go about it?

 

[skand]

yes,why not. :)

Angle between lines joining $$(x_1,y_1) \&\(x_2,y_2)=tan^{-1}\left( \frac{y_2-y_1}{x_2-x_1}\right)$$

 

[darkelf]

Angles between lines joining? If you have a single slope that doesn't intercept at the x or y axis?

 

[Cantab Morgan]

Have another look at skand's answer. Slope means rise over run, right? So if you have the slope, then you have the tangent of the angle.