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Prove that (1+\cos \theta+i \sin \theta)^{n}+(1+\cos \theta-i \sin \theta)^{n}=2^{n+1} \cos ^{n}\left(\frac{\theta}{2}\right) \cos \left(\frac{n \theta}{2}\right) |
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Answer» Using (cos(x)+i.sin(x))^n=(cos(nx)+i.sin(nx)) , we got the last step thank you for quick help |
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