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# Complex numbers watch

1. Need some help with q5. Im not too sure what to do. Ive attempted a diagram so far haha.

http://m.imgur.com/giWugVJ,oIOlkid
2. Could you post your working out of what you've tried so far?
3. (Original post by Student403)
Could you post your working out of what you've tried so far?
Yeah a diagram so far lol. Im not sure whats going on
4. Alright cool

Remember these are literally just expressions like a, b and c themselves. Get the expression of (A) + i(B) by carrying out the subtractions given, Then remember the formula of r? Using pythagoras's theorem?

And remember how to work out theta? Just plot those as normal
5. (Original post by Student403)
Alright cool

Remember these are literally just expressions like a, b and c themselves. Get the expression of (A) + i(B) by carrying out the subtractions given, Then remember the formula of r? Using pythagoras's theorem?

And remember how to work out theta? Just plot those as normal
Sorry im slightly confused.

Is b-a =(root 3 -2)+i?
|b-a|= root 8. Hm idk
6. (Original post by Super199)
Sorry im slightly confused.

Is b-a =(root 3 -2)+i?
|b-a|= root 8. Hm idk
hmm I've just reread the question

Let me tag in Zacken to save the day
7. (Original post by Super199)
Sorry im slightly confused.

Is b-a =(root 3 -2)+i?
|b-a|= root 8. Hm idk
They want you to draw an argand diagram, plot the complex numbers and think of triangles. Does that help in anyway?

E.g: draw a and b, then b-a is the line connecting the endpoint of a to the endpoint of b
8. (Original post by Zacken)
They want you to draw an argand diagram, plot the complex numbers and think of triangles. Does that help in anyway?

E.g: draw a and b, then b-a is the line connecting the endpoint of a to the endpoint of b
One thing that's confusing me is how they say use it to express it exactly in the form re^itheta. How does that work? Shouldn't it be done by calculation?
9. (Original post by Student403)
One thing that's confusing me is how they say use it to express it exactly in the form re^itheta. How does that work? Shouldn't it be done by calculation?
Haven't worked through it myself, but it might be easier to find r and the theta using geometry methods (soh cah toa/cosine/sine rule) instead of manual calculation.
10. (Original post by Zacken)
Haven't worked through it myself, but it might be easier to find r and the theta using geometry methods (soh cah toa/cosine/sine rule) instead of manual calculation.
Hmm fair enough. Just that they're not very nice values if you want to give them exactly
11. (Original post by Student403)
Hmm fair enough. Just that they're not very nice values if you want to give them exactly
Hmm, you're right, that gives you horrible 'exact' answers
12. (Original post by Zacken)
Hmm, you're right, that gives you horrible 'exact' answers
Strange!

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