Assignment:
At 10:00 a.m., train A leaves the station heading east at 40 m.p.h. At 11:00 a.m., train B leaves the same station heading North 30 degrees W (theta = 120 degrees) at 70 m.p.h. How fast is the distance changing at 12:00 noon. Give both the exact answer and a one decimal place approximation.
You may find it helpful to plot the the positions of the trains and station at noon on a set of coordinate axes, the law of cosines is useful too.
Provide complete and step by step solution for the question and show calculations and use formulas.