Question

2 cossquare x – 3 cos x + 1 = 0​

Answer 1

Answer:

it can be written as

2cos^2 -2cos -cos+1=0

2cos(cos-1)-1(cos-1)=0

(2cos-1)(cos-1)=0

cos=1/2 i.e. theta is 60°

cos=1 i.e theta is 0°

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Answer 2

Answer:

$= > 2 \: {cos}^{2} x - 3cos \: x + 1 = 0$$=> 2{cos}^{2}x-2cosx-cos\: x+1=0$

$= > 2cosx(cosx - 1) - (cosx - 1) = 0$

$= > (cosx - 1)(2cosx - 1) = 0$

$= > cosx - 1 = 0$

$= > cosx = 1 \\ = > x = 2n\pi$

$= > 2cosx - 1 = 0$

$= > cosx = \frac{1}{2} = cos \frac{\pi}{3}$

$= > x = 2n\pi + - \frac{\pi}{3}$

Hence x= 2nπ , x= 2nπ + π/3

x = 2nπ - π/3