A particle's position r as a function of time t is given by r=at3i^+(btct4)j^ where a=2.57m/s3,b=7.4m/s, and c= 5.59m/s4. At a time t=7.85, find the angle that the acceleration vector makes with respect to the x direction. Give your answer in degrees in the range from -180 to 180 degrees with an accuracy of 0.1 degree. If your answer is outside this range, add or subtract a full circle (360 degrees) to get an answer within this range. Note that angles measured in the counter-clockwise direction from the x direction are positive, and angles measured in the clockwise direction from the x direction are negative. Also note that the tangent of is the same as the tangent of +180, so the inverse tangent function may give you an answer that's off by 180 degrees. So figure out what quadrant the vector should be in and add or subtract 180 degrees to get the answer into the correct quadrant if needed