Question

Diketahui a adalah sudut lancip dan .
nilai

Answer 1

Cos ¹/₂ a = √(x²-1) / (x)
sin² ¹/₂ a = 1 - cos² ¹/₂ a
sin² ¹/₂ a = 1 - (x²-1)/x²
sin² ¹/₂ a = (x² - x² + 1)/x² = 1/x²

sin² A = (sin A)² = (2 sin ¹/₂ a. cos ¹/₂ a)²
sin² A = 4 (1/x²) (x²-1)/x² 
sin² A = 4(x²-1)/x⁴

sin A = √ {4/x² (x²-1)}
sin A = ²/ₓ √(x²-1)