Faces of mathematics : an introductory course for college students / A. Wayne Roberts, Dale E. Varberg. Roberts, A. Wayne (Arthur Wayne), 1934- Varberg, Dale E., joint author. Mathematics. QA39.2 .R6 1978 510 ROF Includes indexes. New York : Crowell, c1978. c1978. 1978 Text xiii, 456 p. : eng The Thomas Y. Crowell series in mathematics