Rate of Change and Differentiation

Question

Particle moving along hyperbola xy=4 as it reachs (2,2) Y coordinate is decreasing at rate of 3cm/s

How fast is x-coordinate changing?

Use differentiation,

Answer 1

xy = 4

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

y(dx/dt) = -x(dy/dt)

dx/dt = -(x/y)(dy/dt)

Now just plug in the values given in the problem to get your answer.