Let α,β be the roots of x2−2xcos⁡ϕ+1=0  then the equation whose roots are αn and βn is

# Let   then the equation whose roots are  is

1. A

${\mathrm{x}}^{2}-2\mathrm{xcos}\mathrm{n\varphi }-1=0$

2. B

${\mathrm{x}}^{2}-2\mathrm{xcos}\mathrm{n\varphi }+1=0$

3. C

${\mathrm{x}}^{2}-2\mathrm{xsin}\mathrm{n\varphi }+1=0$

4. D

${\mathrm{x}}^{2}+2\mathrm{xsin}\mathrm{n\varphi }-1=0$

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### Solution:

The given equation is  ${\mathrm{x}}^{2}-2\mathrm{xcos}\mathrm{\varphi }+1=0$

$\therefore$ Required equation is
${\mathrm{x}}^{2}-2\mathrm{xcos}\mathrm{n\varphi }+1=0$

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