Please check my work for:

The minute hand of a steeple clock is 4 feet long, and the hour hand is 3 feet long. How fast is the distance between the tips of the hands changing at 3 o'clock. (Hint says to use the law of cosines to computer the distance between the tips of the hands. Also, I determined that the relative rates of change of the angle between the two hands is -11(pi)/6 at 3 o'clock.

Question

Please check my work for:

The minute hand of a steeple clock is 4 feet long, and the hour hand is 3 feet long.  How fast is the distance between the tips of the hands changing at 3 o'clock. (Hint says to use the law of cosines to computer the distance between the tips of the hands.  Also, I determined that the relative rates of change of the angle between the two hands is -11(pi)/6 at 3 o'clock.

anonymous · Answer

The answer I came up with is -22(pi)/5 feet per hour.

thomas5267 · Answer

My answer is $\frac{-11\pi}{5}$.  Not sure which is the right answer.

anonymous · Answer

@thomas5267 I've looked over my work, and keep coming up with the same answer, but yours looks to be more correct and logical...can you help me work through this?