# CBSE Class 10 Maths – Introduction to Trigonometry Formula

#### 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 Practice Test – Trigonometry

Class 10 Maths – Notes , Important Questions and Solutions – Trigonometry

Class 10 Maths Worksheet ( Some Applications of Trigonometry )