+ 3) the resultant of the two harmonic oscillations

Input := 

Plot[wave1 + wave2, {t, 0, 0.1}]
Output =

-Graphics-
Input := 

Plot[wave1 + wave2, {t, 0, 1},
 PlotPoints -> 200]
Output =

-Graphics-
Input := 

Play[wave1 + wave2, {t, 0, 1}]
Output =

-Sound-