1 Trigonometric ratio : In Δ ABC, ΔB = 90°. For Angle A,
sin A = Perpendicular / Hypotenuse = Opposite side / Hypotenuse
cos A = Base / Hypotenuse = adjacent side / Hypotenuse
tan A = Perpendicular / Base = Opposite side / adjacent side
cot A = Base / Perpendicular = adjacent side / opposite side
sec A = Hypotenuse / Base = Hypotenuse / adjacent side
cosec A = Hypotenuse / Perpendicular = Hypotenuse / Opposite side
2. Opposites
sin θ = 1 /cosec θ , cosec = 1 / sinθ
cos θ = 1 / sec θ , sec = 1/ cos θ
tan θ= 1 / cot θ , cot = 1/ tan θ
tan θ = sinθ / cos θ , cot θ = cos θ / sin θ
3. Identities
sin² θ + cos² θ = 1 ⇒ sin² θ = 1 – cos² θ and cos² θ= 1 – sin² θ
1 + tan² θ= sec² θ ⇒ tan² θ= sec² θ – 1 and sec² θ – tan² θ = 1
1 + cot² θ = cosec² θ ⇒ cot² θ= cosec² θ– 1 and cosec² θ– cot² θ = 1
4. Trigonometric ratios of some specific angles
5. Trigonometric ratios of complementary angles
sin (90° – θ) = cos θ
cos (90° –θ) = Sin θ
tan (90° –θ) = cot θ
cot (90° –θ) = tan θ
sec (90° –θ) = cosec θ
cosec (90° –θ) = sec θ
Class 10 Maths – Notes , Important Questions and Solutions – Trigonometry
Class 10 Maths Worksheet ( Some Applications of Trigonometry )