Which Wave Function Describes a Wave Moving in the -x Direction?

[kpx001]

Homework Statement

which of the wave functions describe a wave that moves in the -x direction
y(x,t) =Asin(-kx-wt)
y(x,t)=Asin(kx+wt)
y(x,t)=Acos(kx+wt)

Homework Equations

wave function

The Attempt at a Solution

I know B and C both move left looking at the phase (kx+wt) because its +, however I have no idea about A. I don't know how to convert between sin and cosine or any knowledge of adding pi/2 or anything. can anyone explain this to me? Thank you

 

[kuruman]

A trig identity says sin(-x) = - sin(x). This should help.