1. The problem statement, all variables and given/known data A wave on a string has a wave function with the form of: y(x,t)=0.02sin(6.35x+2.63t) Find the shortest time for the displacement of the string at any point on the chain changes from 0.01m to -0.02m. 3. The attempt at a solution The answer said we can set x=0. And 0.01=0.02sin(2.63t1), 3*3.14/2=2.63t2, where t1 is initial time and t2 is final time. then t1=0.2s and t2=1.6s, so t2-t1=1.4s But I don't understand where 3*3.14/2=2.63t2 comes from. And when I tried to follow the answer and calculate, the calculated answers don't seem to be correct.... So how should I solve it? Thank you very much.