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cos x=-(1)/(2)

cosx=12 \cos x=-\frac{1}{2}

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Q. cosx=12 \cos x=-\frac{1}{2}
  1. Identify angle with cosine: Identify the angle whose cosine is 12-\frac{1}{2}. Using trigonometric identities or a unit circle, we know cos(120°)=12\cos(120°) = -\frac{1}{2} and cos(240°)=12\cos(240°) = -\frac{1}{2}.
  2. Convert angles to radians: Convert the angles to radians because most mathematical problems require answers in radians.\newline120°=120×(π/180)=2π/3120° = 120 \times (\pi/180) = 2\pi/3 radians,\newline240°=240×(π/180)=4π/3240° = 240 \times (\pi/180) = 4\pi/3 radians.
  3. Consider periodic nature: Consider the periodic nature of the cosine function. Cosine has a period of 2π2\pi, so the general solutions are: x=2π3+2πkx = \frac{2\pi}{3} + 2\pi k and x=4π3+2πkx = \frac{4\pi}{3} + 2\pi k, where kk is any integer.

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