OI#5&6 Trigonometry

radians to degrees

pi radians = 180 degrees 2 pi radians = 360 degrees

cot2pi

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sec2pi

1

Fundamental trigonometric identities

Reciprocal identities: secθ=1/cosθ cscθ=1sinθ cotθ=1/tanθ cosθ=1/secθ sinθ=1/cscθ tanθ=1cot/θ Quotient identities: tanθ=sinθ/cosθ cotθ=cosθ/sinθ Pythagorean identities: sin^2θ+cos^2θ=1 1+tan^2θ=sec^2θ 1+cot^2θ = csc^2θ Cofunction identities: sin(π/2 - θ) = cosθ cos(π/2 - θ) = sinθ tan(π/2 - θ) = cotθ cot(π/2 - θ) = tanθ sec(π/2 - θ) = csc θ csc(π/2 - θ) = sec θ Odd/Even function identities: sin(−θ)= −sinθ cos(−θ)= cosθ tan(−θ) = -tanθ csc(−θ) = −cscθ sec(−θ) = secθ cot(−θ) = -cotθ