Question

Basic vector question

Answer 1

I have two vectors:
A=(23,59)
B=90,-150)

I need to do B-5A

So I got that is (-25,-445)

I need to calculate magnitude (445.7) and the angle.

I try to use the inverse angle, but it is returning me a positive 86.8, not a negative one

Answer 2

right, calculator will give you only 86.8
you need to manually figure out the exact value,
(-25,-445) is in 3rd quadrant,
hence we should manually subtract 180 from the angle

Answer 3

So you say it is -93.2?

Answer 4

When do I substract? When it is in 2nd or 3rd?

Answer 5

1st quadrant -- do nothing
2nd quadrant -- add 180
3rd quadrant -- subtract 180
4th quadrant --do nothing

Answer 6

applicable only for tan, and those actions should be performed to the calculator answer...
for example , if the quadrant is 4, calculator itself will give you negative angle, hence do nothing

Answer 7

Thanks a lot

Answer 8

welcome ^_^