Submitted by spacedino101 on Tue, 03/28/2017 - 16:58
Forums:
Maybe I'm reading it wrong, but how come S1, S2, S3 are real when S1 = z1 + z2 + z3 = r(cos(theta) + isin(theta)) + r^2(cos(2theta) + isin(2theta)) + .... ?
Thank you!
Submitted by spacedino101 on Tue, 03/28/2017 - 16:58
Maybe I'm reading it wrong, but how come S1, S2, S3 are real when S1 = z1 + z2 + z3 = r(cos(theta) + isin(theta)) + r^2(cos(2theta) + isin(2theta)) + .... ?
Thank you!
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Can't really see what you're
Can't really see what you're asking: just checked the question and there's no mention of $S1, S2$ and $S_3$ being real, at least not at the outset?
Sorry! Forgot to say that
Sorry! Forgot to say that that's what it said in the mark scheme on the ATS website
They're saying that the $S_i$
They're saying that the $S_i$ are real if the $S_i$ obey the conditions imposed in part (iii) of the question. That is, those conditions on $\theta_k$ and $r_k$ imply that $\Im(S_i) = 0$; so they show that the $S_i$ are real. If there's a step of the proof you don't understand, point it out.