The length of the rope is L=√h? +s？

Rope speed v0=dL/dt=(dL/ds)(ds/dt)

dL/ds=s/√h？ +s？

Ship speed v=ds/dt

So there is: v0=vs/√h? +s？

So the ship speed v=(v0√h? +s？ )/s

For example:

Let the minimum time delta bait,

a=(v'-v)/△t

=((v0/cos(θ+△θ))-(v0/cosθ))/△t

=((v 0/(cosθcos△t-sinθsin△t))-v 0/cosθ)/△t

Delta t is the minimum value, so sin delta t = delta t, cos delta t =1.

So sin delta t = v' sinθdelta dut/√( s? +h？ )=tanθv0△t/√(s？ +h？ )

Bring in a and get a=v0? h？ /s？

Extended data:

If the function f(x) is in x? Definition of a neighborhood d, x division? All points of have f (x)

Similarly, if all points in d except x0 have f (x) >; f(x？ ), just call f(x? ) is the minimum value of the function f(x).

The concept of extreme value comes from the problem of maximum and minimum value in mathematical application. According to the law of extremum, every continuous function defined in a bounded closed region must reach its maximum and minimum. The problem is to determine at which point it reaches the maximum or minimum. If the extreme point is not a boundary point, then it must be an interior point. Therefore, the first task here is to find a necessary condition for an interior point to become an extreme point.

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