Physics
posted by Emily .
Two displacement waves are added resulting in constructive interfernce and these waves have the same period T = 1.00 s are described mathematically by:
y1 = (3.0 m) cos[ 2ðt/T + ð ]
y2 = (1.00 m) cos[ 2ðt/T + 2ð ]
(i) What is the resultant displacement at time t = 1?

Sorry y1=3cos[2pie*t/T + pie]
and y2=1cos[2pie*t/T + 2pie]