Answer:
Option (1)
Step-by-step explanation:
2cos²(75°) - 1 = cos2(75°) [By using identity 2cos²a - 1 = cos2a]
= cos(150°)
= cos(90 + 60)°
= -sin(60°) [Since, cos(90 + θ) = -sinθ]
= [tex]-\frac{\sqrt{3}}{2}[/tex]
Therefore, solution of the given expression is [tex](-\frac{\sqrt{3}}{2})[/tex].
Option (1) will be the correct option.
