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Question-226362




Question Number 226362 by Rojarani last updated on 26/Nov/25
Answered by Frix last updated on 26/Nov/25
α=(√3)e^(−i((3π)/4))   β=(√3)e^(i((3π)/4))   α^n +β^n =2×3^(n/2) cos ((3nπ)/4)  (((α^(23) +β^(23) )+(α^(14) +β^(14) ))/((α^(15) +β^(15) )+(α^(10) +β^(10) )))=((−177147(√6)+0)/(−2187(√6)+0))=  =81
$$\alpha=\sqrt{\mathrm{3}}\mathrm{e}^{−\mathrm{i}\frac{\mathrm{3}\pi}{\mathrm{4}}} \\ $$$$\beta=\sqrt{\mathrm{3}}\mathrm{e}^{\mathrm{i}\frac{\mathrm{3}\pi}{\mathrm{4}}} \\ $$$$\alpha^{{n}} +\beta^{{n}} =\mathrm{2}×\mathrm{3}^{\frac{{n}}{\mathrm{2}}} \mathrm{cos}\:\frac{\mathrm{3}{n}\pi}{\mathrm{4}} \\ $$$$\frac{\left(\alpha^{\mathrm{23}} +\beta^{\mathrm{23}} \right)+\left(\alpha^{\mathrm{14}} +\beta^{\mathrm{14}} \right)}{\left(\alpha^{\mathrm{15}} +\beta^{\mathrm{15}} \right)+\left(\alpha^{\mathrm{10}} +\beta^{\mathrm{10}} \right)}=\frac{−\mathrm{177147}\sqrt{\mathrm{6}}+\mathrm{0}}{−\mathrm{2187}\sqrt{\mathrm{6}}+\mathrm{0}}= \\ $$$$=\mathrm{81} \\ $$

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