Ekman
Well-Known Member
- Joined
- Oct 23, 2014
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- HSC
- 2015
Re: HSC 2015 4U Marathon
![](https://latex.codecogs.com/png.latex?\bg_white cisx+ cis2x+ cis3x+cis4x+...+cisnx = cisx+(cisx)^2+(cisx)^3+...+(cisx)^n )
Then made the whole geometric series sum and got all imaginary bits:
![](https://latex.codecogs.com/png.latex?\bg_white \frac{\sin(\frac{\pi}{2015})}{1-cos(\frac{\pi}{2015})} = 1282.7885...)
![](https://latex.codecogs.com/png.latex?\bg_white $ However, $ cot(\frac{\pi}{3030})=964.478...)
But if I was to sub in 4030 instead of 3030, it would get the same answer...
I did something a little different. I made a geometric sum of this:a little change would make a good question:
![]()
Then made the whole geometric series sum and got all imaginary bits:
But if I was to sub in 4030 instead of 3030, it would get the same answer...