MQ14 --- Trigonometry

sinθ / cosθ = tanθ
sin²θ / cos²θ = tan²θ
sin²θ / (1 - sin²θ) = tan²θ
sin²θ = tan²θ - sin²θ tan²θ
sin²θ (1 + tan²θ) = tan²θ
sin²θ = tan²θ / (1 + tan²θ)
sinθ = ± tanθ / √(1 + tan²θ)

tanθ=x/1
對邊:x,鄰邊:1,斜邊:√(1+x²)
sinθ=±x/√(1+x²)=±tanθ/√(1 + tan²θ)