1. The problem statement, all variables and given/known data A patrol car is 50 ft from a long warehouse. The revolving light on top of the car turns at a rate of 30 rotations per minute. How fast is the beam of light moving along the warehouse wall when the beam makes a 45° angle with the line perpendicular from the light to the wall? 2. Relevant equations 3. The attempt at a solution First I started out by setting θ as a function of x : tanθ=(x/50)→θ=arctan(x/50). So when θ=45°, x=50ft. dθ/dt is 30(2∏)=60∏. So taking the derivative: dθ/dt=[(50)/(502+x2)]dx/dt. After substituting values, 60∏=(0.01)dx/dt→dx/dt=6000∏ ft/min. Is this right?