Trigonometry – All Formulas + Concept Summary

 

📘 Basic Trigonometric Ratios:

sin θ, cos θ, tan θ, cot θ, sec θ, cosec θ

sin 0° = 0, cos 0° = 1, tan 0° = 0

sin 30° = 1/2, cos 30° = √3/2, tan 30° = 1/√3

sin 45° = 1/√2, cos 45° = 1/√2, tan 45° = 1

sin 60° = √3/2, cos 60° = 1/2, tan 60° = √3

sin 90° = 1, cos 90° = 0, tan 90° = ∞

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📘 Trigonometric Identities:

1. sin²θ + cos²θ = 1  

2. 1 + tan²θ = sec²θ  

3. 1 + cot²θ = cosec²θ

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📘 Other Formulas:

tan θ = sin θ / cos θ  

cot θ = cos θ / sin θ  

sec θ = 1 / cos θ  

cosec θ = 1 / sin θ

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📘 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

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📘 Formulas in Triangle:

Area = (1/2) × a × b × sin C  

Law of Sines: a/sin A = b/sin B = c/sin C  

Law of Cosines: c² = a² + b² – 2ab cos C

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📌 Posted by: Sarthak Prakash Patil