The flight of a bird follows the curve x=t-cos(t), y=3-2sin(t)... where 0<=t<=4pi is the time in seconds. a) What times is the bird flying horizontally? find the (x,y) coordinates of the corresponding points. b) What times is the bird flying vertically? find the (x,y) coordinates of the corresponding points. my work: i found dx/dt=1+sin(t) dy/dt=-2cos(t) and therefore dy/dx=(-2cos(t))/(1+sin(t)) The bird flies horizontally when dy/dt=0 and dx/dt=/=0, right? dy/dt=0 at t=pi/2 and 3pi/2. However, dx/dt=0 when 3pi/2, so would it be just pi/2? Same problem for part b. The bird flies vertically when dx/dt=0 and dy/dt=/=0. dx/dt=0 at t=3pi/2, but dy/dt equals zero then. What does this mean for the bird's flight?