Answer:
<em>-1.031 m/s or </em>
Step-by-step explanation:
We take the length of the rope from the dock to the bow of the boat as y.
We take x be the horizontal distance from the dock to the boat.
We know that the rate of change of the rope length is
= -1 m/s
We need to find the rate of change of the horizontal distance from the dock to the boat =
= ?
for x = 4
Applying Pythagorean Theorem we have
.... equ 1
solving, where x = 4, we have



Differentiating equ 1 implicitly with respect to t, we have

substituting values of
x = 4
y = 
= -1
into the equation, we get

= <em>-1.031 m/s</em>