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# FP2 - Complex roots help please watch

1. How do you go about finding the modulus of the midpoint of z1 and z2? I know how to find the argument of the midpoint which is pie/8, but finding the modulus is confusing to me =S

thanks!
2. (Original post by TimetoSucceed)

How do you go about finding the modulus of the midpoint of z1 and z2? I know how to find the argument of the midpoint which is pie/8, but finding the modulus is confusing to me =S

thanks!
Some simple geometry will do it. Mark the lines of equal length. What's the angle at the centre?
3. (Original post by ghostwalker)
Some simple geometry will do it. Mark the lines of equal length. What's the angle at the centre?
pie/2 i think, maybe i misunderstood what you said lol
4. (Original post by TimetoSucceed)
pie/2 i think, maybe i misunderstood what you said lol
That's correct. So you have a right-angled isosceles triangle with sides of length root(3). And you've bisected the hypotenuse.
5. ok so the big triangle is a right angled isosceles, so the two other angles are 45 each right?

i get this, is this correct? lol

if it is i can just do sine rule i guess to work out the side i need, but im still unsure if the angles are correct.

edit: i think im way wrong lol, or maybe my drawing is wayyy off to scale
6. (Original post by TimetoSucceed)
...
Your angles are right. Your drawing is a bit "way off". You can finish it with pythagoras, or whatever.
7. (Original post by ghostwalker)
Your angles are right. Your drawing is a bit "way off". You can finish it with pythagoras, or whatever.
thanks, i now understand this =].

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