Learn more about Learn Trig.

Name a triangle's sides relative to an angle.

Define trig functions.

Memorize values of Sine, Cosine, Radians, and Degrees.

Explore how angles, side names, and function ratios correspond.

Since "Tri" means three, "Gon" means angle, and "Metry" means measurements, trigonometry means triangular measurements.

Sin = Opp/Hyp

Cos = Adj/Hyp

Tan = Opp/Adj

Csc = Hyp/Opp

Sec = Hyp/Adj

Cot = Adj/Opp

Sin(-Θ) = -Sin(Θ)

Cos(-Θ) = Cos(Θ)

Tan(-Θ) = -Tan(Θ)

Sin = 1/Csc

Cos = 1/Sec

Tan = 1/Cot

Csc = 1/Sin

Sec = 1/Cos

Cot = 1/Cot

Sin^{2}Θ + Cos^{2}Θ = 1

Tan^{2}Θ + 1 = Sec^{2}Θ

Cot^{2}Θ + 1 = Csc^{2}Θ

Sin(Θ ± π) = Sin(Θ)Cos(π) ± Cos(Θ)Sin(π)

Sin(Θ ± π) = Cos(Θ)Cos(π) ∓ Sin(Θ)Sin(π)

Tan(Θ) ± Tan(π)

Tan(Θ ± π) = ----------------

1 ∓ Tan(Θ)Tan(π)

Θ = Θ * 2π * (± C)

*(C is any Integer)*