hello,

use sin(30°) = 0.5 and cos(30°) = 0.5*√(3).

Then the position of the ship S is

The second vessel V is located on the east axis and it's position is

Now use the distance formula:

The minimum of (D(t))² occurs if the first derivative of (D(t))² is zero:

. Now

Plug in this value into the equation and calculate D: