quick qn (1 Viewer)

[deyveed]

In complex numbers, when theres a complex number AB that makes a right angle with OA, how do you know if AB is iOA or -iOA?

 

[Rahul]

if its anticlockwise then its iOA, if it is clockwise then its -iOA.
i dont know i am guessing.

 

[deyveed]

but the right angle isn't at the origin. does it still apply?

 

[Rahul]

yeh, it would be for any complex number.
maybe someone can confirm this...

 

[deyveed]

Ok.
What about if they give you complex numbers OA and OB and they want you to find AB

Do you write OA-OB or OB-OA? and why?

 

[BlackJack]

Hmm... for the first, put them tail to tail as vectors, then think of multiplying by i as rotating by 90 anticlockwise. So yeah.

THe second, head minus tail... OB- OA. Think of it as:
You want to travel the distance and direction AB, doesn't matter where you are, but you can do it by going OB and then AO (-OA) or just going AB. Best to illustrate with the vector arrows.