# Rodrigues rotation

I do not understand the difference between these two equations:

1. from wikipedia:

https://en.wikipedia.org/wiki/Rodrigu...

2. from open CV doc:

http://docs.opencv.org/2.4/modules/ca...

Where is the **cos(θ)** gone on the wiki page in the formula 1. ?

Shouln't it be: v_{rot} = cos(θ)v + sin.... ?

Then on the wiki page, there is no more cos(θ) in the definition of R...

Or did I miss something?