Complex Series Magnitude
If $ w=\cos40^\circ+i\sin40^\circ $, then \[|w+2w^2+3w^3+ \dots +9w^9|^{-1}\]can be expressed in the form $ \frac{a}{b} \sin n^\circ, $ where $ a $ and $ b $ are relatively prime positive integers, and $ n $ is a positive integer smaller than 90. Find $ a + b + n $.
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- $\frac{a}{b}$
- .
- 0
- =
- %
- $a^n$
- $a^{\circ}$
- $a_n$
- $\sqrt{}$
- $\sqrt[n]{}$
- $\pi$
- $\ln{}$
- $\log$
- $\theta$
- $\sin{}$
- $\cos{}$
- $\tan{}$
- $($
- $)$
- $[$
- $]$
- $\cap$
- $\cup$
- $,$
- $\infty$