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討論串[中學] 100 鳳新高中教甄<代理>
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內容預覽:
還是可以湊. cos3/7π-cos2/7π + cos1/7π. = (2sin2/7π*cos3/7π-2sin2/7π*cos2/7π + 2sin2/7π* cos1/7π) / 2sin2/7π. = (sin5/7π+ sin(-1/7π) - sin4/7π + sin3/7π + s
(還有7個字)
內容預覽:
z = exp(jπ/7) = cos(Θ) + j sin(Θ). z^7 + 1 = 0. (z+1)(z^6 - z^5 + z^4 - z^3 + z^2 - z + 1) = 0. 1 = (z-z^6) - (z^2-z^5) + (z^3-z^4) = Re((z-z^6) - (z^
(還有186個字)
內容預覽:
Q2.. t:=\theta. 7t = \pi. cos(t) = -cos(6t). cos(2t) = -cos(5t). cos(3t) = -cos(4t). f = cos(3t) - cos(2t) + cos(t). 2f = -cos(6t)+cos(5t)-cos(4t)+cos
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