Collaborative collection of useful userRPL snippets

[peacecalc]

Hello Paul,

why you don't like to use that expression for finding the angle between to vectors?

\[ angle between(\vec{v}_1,\vec{v}_2)= arccos\left(\frac{\vec{v}_1 \cdot \vec{v}_2}{|\vec{v}_1 || \vec{v}_2|}\right) \].

It is brutal force... but in RPL it is easy to manage:

Code:

<< \-> v1 v2 
    << v1 v2 DOT v1 ABS / v2 ABS / ACOS >>
>>

Sorry I forgot if the angle is greater than 90 degrees (or pi/2) then take 180 degrees minus the result above (or pi - result).
Double sorry, I've now understand your display task in your last post.