The length L (in meters) of a pendulum is increasing at a rate of 0.020 m/s as its string slowly stretches. Simultaneously, the angle θ (in radians) that the pendulum makes with the vertical is increasing at 0.30 rad/s. The horizontal displacement of the pendulum bob from its lowest point is x=Lsinθ. Find dtdx when L=1.5 m and θ=0.40 rad. Provide the answer in m/s.