a point is moving along the graph of the given function such that dx/dt is 2 cm/sec. find dy/dt for the given values of x

y=cosx

i ended up changing this to dy/dt=-sinx*2

x = pi/6 -> dy/dt = -1

x = pi/4 -> dy/dt = -squareroot(2)

x = pi/3 -> dy/dt = -squareroot(3)

sorry if this is a little messy jw if my awnsers are correct for each x value