mixing vs undertaking

mixing

noun
  • The act, or the result of making a mixture. 

adj
  • Of a stochastic process, to be asymptotically independent (in a precise mathematical sense). 

undertaking

noun
  • The act of one who undertakes (in either sense). 

  • A promise or pledge; a guarantee. 

  • That which is undertaken; any business, work, or project which a person engages in, or attempts to perform; an enterprise. 

  • The business of an undertaker, or the management of funerals. 

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