The sine and cosine functions relate angles to their sine and cosine values. They are fundamental to trigonometry.
Identities: sin²θ + cos²θ = 1
The tangent function is the ratio of sine to cosine, while cotangent is its reciprocal.
Identities: tanθ = sinθ/cosθ
The secant and cosecant functions are reciprocals of cosine and sine, respectively.
Identities: secθ = 1/cosθ, cscθ = 1/sinθ