Answer:
20∠140°
Explanation:
You want the sum of -10∠-40° and 10∠-220°.
Alias
Writing both expressions with positive numbers, we have ...
-10∠-40° = 10∠(-40+180)° = 10∠140°
and
10∠-220° = 10∠(-220+360)° = 10∠140°
Sum
Then the sum is ...
10∠140° +10∠140° = 20∠140°
Since the angles are the same, the magnitudes add.
The sum is 20∠140°.
__
Additional comment
A negative magnitude is the same as a positve magnitude in the opposite direction: 1∠0° = -1∠180°.
<95141404393>