Exercise 1:
The easiest way to compute powers of complex numbers is to write them in the form

In this form, you have

The magnitude of the number is given by

So, we have

As for the angle, we have

So, we have

Finally,

Exercise 2:
You simply have to compute the trigonometric function:

So, we have

Answer:
Step-by-step explanation:
Using vector method to solve it
Resultant can be given by


R=671.12 Km/hr
The angle made by resultant with 700 km/hr is 
using sine rule



i think it’s is a for the first one
Usually a ratio will compare two numbers by division