Im finding these Complex Q's quite complex(more q's) (1 Viewer)

[scardizzle]

http://i.imgur.com/t5YSB.jpg
Half Yearly's are tomorrow so any help would be great

I have no idea how to do d (ii), something to do with an angle subtended at the centre of a circle is double that at the circ???

for e) how do i decide whether the vector between 2 points is z1 - z2 or z2 - z1?

 

[khorne]

What was your answer for e?

You decide by say z-w is the line from w to z (arrow pointing at z)

For e)

|Q|/|p| =|r|/|a|
to find the mod of Q, then find the arg of P, and add it to the arg of R

 

[ninetypercent]

you are correct for d (ii)

 

[scardizzle]

wow, i didnt know you oculd do that, should my answer be 1 + 5i?

 

[scardizzle]

you are correct for d (ii)

but doesnt give the opposite result wouldnt 2arg(z-3) = argz

edit: oops double post

 

[khorne]

Easier method:

|R| = |Q|/|P|
|q| = |RP|

arg(q) = arg (r) + arg(p)

therefore q = QP (product)

 

[Rezen]

di) This is simply the locus of a circle with radius three and centre (3,0) in the argand diagram.

ii)

(sorry for any errors, first time using this thing)
question e is straight out of your textbook (most likely, i know its in the terry lee and cambridge books and i have a feeling even coroneus has it.)