calculation vs trigonometry

calculation

noun
  • The act or process of calculating. 

  • Reckoning, estimate. 

  • The result of calculating. 

  • An expectation based on circumstances. 

  • The act or process of imagining sequences of potential moves and responses without actually moving the pieces. 

trigonometry

noun
  • The branch of mathematics that deals with the relationships between the sides and angles of (in particular) right-angled triangles, as represented by the trigonometric functions, and with calculations based on said relationships. 

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