1. The problem statement, all variables and given/known data I don't have an actual problem but is what I am trying to make sure I have clear is... What direction in general is Asin(kx+or-wt) going? Asin(kx+wt) Left Asin(kx-wt) Right Asin(-kx-wt)=-Asin(kx+wt) Left Asin(-kx+wt)=-Asin(kx-wt) Right Acos(kx+wt) Left Acos(kx-wt) Right Acos(-kx+wt)? Acos(-kx-wt)? 2. Relevant equations Asin(kx-wt) is to the right Asin(kx+wt) is to the left Is what I have been taught to help me figure out the direction. 3. The attempt at a solution I am pretty sure the ones I answered are correct but if they're please let me know. My trouble is that as far as I know I can't take a negative out of the cos function like I can the sin function, so the only thing I have thought of thus far... Acos(-kx+wt)=Asin(-kx+wt+pi/2)=-Asin(kx-wt-pi/2) So I would say this goes to the right because it is minus wt. Does that work?