# Formulae

**URL:** <https://forum.kirupa.com/t/formulae/267633>\
**Category:** Uncategorized\
**Created:** [August 4, 2008, 9:28am UTC](https://forum.kirupa.com/t/formulae/267633 "2008-08-04T09:28:19Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![rahul\_7star](https://avatars.discourse-cdn.com/v4/letter/r/e36b37/32.png) [@rahul\_7star](https://forum.kirupa.com/u/rahul_7star)\
**Post date:** [August 4, 2008, 9:28am UTC](https://forum.kirupa.com/t/formulae/267633/1 "2008-08-04T09:28:19Z")

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wer we use…x= r cos(angle) and y= r sin(angle) ( is this for poviding motion to object)

and why we use

angle=Math.atan(yspeed/(xspeed \*-1))/math.Pi/180…

is this for cal angle …wats the meaning of arc tangent…