gen up vs investigate

gen up

verb
  • To study in detail; to familiarize oneself with all available information. 

  • To inform or teach with all relevant details; to brief. 

investigate

verb
  • To inquire into or study in order to ascertain facts or information. 

  • To examine, look into, or scrutinize in order to discover something hidden or secret. 

  • To conduct an inquiry or examination. 

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