Trigonometry Formulas - Class 11 CBSE
1. Trigonometric Ratios
sinθ = Perpendicular / Hypotenuse
cosθ = Base / Hypotenuse
tanθ = Perpendicular / Base
cosecθ = 1/sinθ, secθ = 1/cosθ, cotθ = 1/tanθ
2. Fundamental Identities
sin²θ + cos²θ = 1
1 + tan²θ = sec²θ
1 + cot²θ = cosec²θ
3. Sum and Difference Formulas
sin(A±B) = sinA cosB ± cosA sinB
cos(A±B) = cosA cosB ■ sinA sinB
tan(A±B) = (tanA ± tanB) / (1 ■ tanA tanB)
4. Double Angle Formulas
sin2θ = 2 sinθ cosθ
cos2θ = cos²θ − sin²θ = 1 − 2sin²θ = 2cos²θ − 1
tan2θ = 2tanθ / (1 − tan²θ)
5. Triple Angle Formulas
sin3θ = 3sinθ − 4sin³θ
cos3θ = 4cos³θ − 3cosθ
tan3θ = (3tanθ − tan³θ) / (1 − 3tan²θ)
6. Product to Sum
1. Trigonometric Ratios
sinθ = Perpendicular / Hypotenuse
cosθ = Base / Hypotenuse
tanθ = Perpendicular / Base
cosecθ = 1/sinθ, secθ = 1/cosθ, cotθ = 1/tanθ
2. Fundamental Identities
sin²θ + cos²θ = 1
1 + tan²θ = sec²θ
1 + cot²θ = cosec²θ
3. Sum and Difference Formulas
sin(A±B) = sinA cosB ± cosA sinB
cos(A±B) = cosA cosB ■ sinA sinB
tan(A±B) = (tanA ± tanB) / (1 ■ tanA tanB)
4. Double Angle Formulas
sin2θ = 2 sinθ cosθ
cos2θ = cos²θ − sin²θ = 1 − 2sin²θ = 2cos²θ − 1
tan2θ = 2tanθ / (1 − tan²θ)
5. Triple Angle Formulas
sin3θ = 3sinθ − 4sin³θ
cos3θ = 4cos³θ − 3cosθ
tan3θ = (3tanθ − tan³θ) / (1 − 3tan²θ)
6. Product to Sum
