Answer: The speed is 22.2 mi/hr and woman is 8° north relative to the surface of the water.
Step-by-step explanation:
Since we have given that
Speed at which woman walks due west = 3 mi/hr
Speed at which ship moving due north = 22 mi/hr
Now it forms "Pythagorus theorem":
So, it becomes,

And the direction of the woman relative to the surface of the water is given by

Hence, the speed is 22.2 mi/hr and woman is 8° north relative to the surface of the water.
If

then

The ODE in terms of these series is



We can solve the recurrence exactly by substitution:


So the ODE has solution

which you may recognize as the power series of the exponential function. Then

1/3 + 5/6 + 5/12
1.583333333333333