Question #af849

2 Answers
Jul 21, 2015

arctan(73)π1.976 radians113.2

Explanation:

First, mark the point (3+7i)=37i in the complex plane. Note that it is in the 3rd quadrant. This means that its argument, or angle (typically taken to be between π and π) is arctan(73)π=arctan(73)π1.976 radians113.2.

You need to subtract π from arctan(yx) in this case because of the fact that the point is in the 3rd quadrant. The arctangent function gives an output between π2 and π2 radians.

Jul 22, 2015

The answer already given is perfectly alright.

Explanation:

Just to make it more clear, it can be stated that argument is measured in anticlockwise direction from positive x axis and it is positive till it is less than 180 degrees. In this case the angle that vector -3-7i makes with x axis is in the third quadrant, hence more than 180 degrees. In this case the angle is measured in clockwise direction , hence it is -1.976 radians.