Answer: second option (counting from the top)
Explanation:
When we have a number:
z = x + y*i
we can represent this with the point:
(x, y).
Now, remember that in polar coordinates, we need to use the variables:
r = distance to the (0, 0), or the "magnitude" of the point.
θ = angle measured counterclockwise from the x-axis.
r is easy to find, is the magnitude, this is calculated as:
r = √(x^2 + y^2)
To find θ, suppose that we have a triangle rectangle, where x is the adjacent cathetus, and y is the opposite cathetus, and θ is the angle as we described it.
We know that:
Tan(θ) = opposite cathetus/adjacent cathetus = y/x
Tan(θ) = y/x
Then:
θ = Tan^-1 (y/x)
Then the correct option is the second option (counting from the top)