# Can't understand the meaning of some symbols

by shakgoku
Tags: meaning, symbols
 P: 29 1. The problem statement, all variables and given/known data This is an extract from elements of mechanics by giovanni. I'[m unable to understand the meaning of $$R^d$$ and $$C^\infty$$ http://flic.kr/p/9K8P7p 2. Relevant equations 3. The attempt at a solution