+Trigonometric functions are mathematical expressions that relate the angles of a [Right Triangle](/wiki/right_triangle) to the ratios of its sides, forming the bedrock of geometry. They are essential for modeling [Periodic Phenomena](/wiki/periodic_phenomena), such as waves and oscillations, extending their utility across physics, engineering, and beyond.
+## See also
+- [Sine](/wiki/sine)
+- [Cosine](/wiki/cosine)
+- [Trigonometry](/wiki/trigonometry)
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