An object with weightWis dragged along a horizontal plane by a force acting along a rope attached to the object. If the rope makes an angletwith the plane, then the magnitude of the force isF=(W)/(sin(t)+cos(t)), whereis a constant called the coefficient of friction. LetW=50lb and=.6.

(a) Find the rate of change of F with respect tot. F'(t)= (b) When is this rate of change equal to zero? Round your answer to the nearest hundredth. t=