as a series of cos@ plz help me i only know the normal way of doing that but i do not know how to apply complex number or exponential
(a+b)^4 = a^4+4a^3b+a^2b^2+4ab^3+b^4 and then let a=1 and b=cos^2(x), you have sin^8(x) = (sin^2(x))^4 = (1-cos^2(x))^4 = 1 - 4cos^2(x) + 6cos^4(x) - 4cos^6(x) + cos^8(x)
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