Both answers are correct. Maybe your z^2 = x^2 + y^2 is more to the point of part a, and notice (maybe it's a trick question to make this point) that the rate of separation doesn't depend on t
2 cars move from same point. one travels north 28mi/hr and the other travels east 70mi/hr
a) write an equation to relate these variables
i did dz/dt = x*dx/dt + y*dy/dt * 1/z
b) at what rate is the distance between the cars increasing 5 hours later?
so z^2 = x^2 + y^2
5*28 = 140
5*70 = 350
z = sqrt(142100)
dz/dt = (140*28 + 350*70)/ 376.96
dz/dt ~= 75.39
did i work it out and calculate correctly?
the problems i'm working w/ don't have an answer key and i'm wondering if this is the right answer as well as proper process to go about a problem like this