cast about vs trip up

cast about

verb
  • To try to find; look around; search. 

  • To plan; plot; contrive. 

trip up

verb
  • To fall or stumble. 

  • To cause (someone) to commit an error, trick into a mistake. 

  • To commit an error, make a mistake. 

  • To cause (someone) to fall or stumble. 

How often have the words cast about and trip up occurred in a corpus of books? (source: Google Ngram Viewer )