Let xy=1 and dy/dt=5. Find dx/dt when x=1.

Question

Let xy=1 and dy/dt=5. Find dx/dt when x=1.

Answer 1

xy = 1

x(dy/dt) + y(dx/dt) = 0

Since xy = 1 and x = 1, y = 1.

So, (1)(5) + (1)(dx/dt) = 0

Therefore, dx/dt = -5