Correct Answer: Option C

Explanation

\(2\sin^{2}\theta = 1 + \cos \theta \implies 2(1 - \cos^{2}\theta) = 1 + \cos \theta\)

\(2 - 2\cos^{2}\theta = 1 + \cos \theta\)

\(2 - 2\cos^{2}\theta - 1 - \cos \theta = 0\)

\(2\cos^{2}\theta + \cos \theta - 1 = 0\)

\(2\cos^{2}\theta + 2\cos\theta - \cos \theta - 1 = 0 \implies 2\cos \theta(\cos \theta + 1) - 1(\cos \theta + 1) = 0\)

\((2\cos \theta - 1)(\cos \theta + 1) = 0 \implies \cos \theta = \frac{1}{2} \)

\(\theta = \cos^{-1} \frac{1}{2} = 60°\)

• If the power of a lens is +2.5D. Calculate the radius of curvature (a). 80cm (b). 40cm (c). 25cm (d).... Answer this

  1 Answers   ·   Physics   ·   4 days ago
• Subjects to learn under petroleum engineering? Answer this

  1 Answers   ·   4 days ago
• what is the cut of mark for medical doctor in university and list all the university? Answer this

  1 Answers   ·   2 days ago