trigonometric function: Quick Facts

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Facts

Also Known As	circular function

Photos

Diagram of a right triangle labeled with sides a, b, and hypotenuse c, alongside formulas for the six trigonometric functions-sine, cosine, tangent, cosecant, secant, and cotangent-each defined by ratios of the triangle's sides.

Diagram of a right triangle with a yellow interior, green outline, green angle θ, red right-angle square, and sides labeled a, b, and c.

Four graphs display the curves of sine, cosine, tangent, and cotangent functions, each labeled with x- and y-axes, key angles in radians, and typical wave or asymptote patterns.

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Topics

tangent cosine sine cosecant cotangent secant law of tangents arc sine law of cosines law of sines special function logistic function Riemann zeta function exponential function Recursive function harmonic function Lagrangian function Hamiltonian function integral transform Propositional function

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Key People

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Abū al-Wafāʾ

Persian mathematician

Equations written on blackboard

Numbers and Mathematics