Proving the Cosine of a Difference Identity

To prove the cosine of a difference identity, use the distance formula to find the lengths of the two versions of the dotted segment.

 

Laura Kinnel —

 
Resource Type
Activity
Tags
cosine  identity  trig 
Target Group (Age)
14 – 19+
Language
English
 
 
 
© 2026 International GeoGebra Institute