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Learn the cosine function (cos) as the ratio of the adjacent side to the hypotenuse in a right triangle. Find the cosine formula, table, properties, graph, inverse, identities, calculus and law of cosines with examples and worksheets.
The ratio of the lengths of the side adjacent to the angle and the hypotenuse of a right-angled triangle is called the cosine function which varies as the angle varies. It is defined in the context of a right-angled triangle for acute angles.
The cosine function is one of the basic functions encountered in trigonometry (the others being the cosecant, cotangent , secant, sine, and tangent ). Let be an angle measured counterclockwise from the x -axis along the arc of the unit circle . Then is the horizontal coordinate of the arc endpoint.
Learn how to define cosine as a ratio of sides of a right triangle or as a coordinate on a unit circle. Find out the values of cosine for common angles and how to use a calculator or a table to find cosine for any angle.
Jun 7, 2024 · cosine, one of the six trigonometric functions, which, in a right triangle ABC, for an angle A, is cos A = length of side adjacent to angle A/ length of hypotenuse. (The other five trigonometric functions are sine [sin], tangent [tan], secant [sec], cosecant [csc], and cotangent [cot].)
Definition of the cosine function for a complex argument. In the complex ‐plane, the function is defined using the exponential function in the points and through the formula: The key role in this definition of belongs to the famous Euler formula that connects the exponential, the sine, and the cosine functions:
The cosine function, along with sine and tangent, is one of the three most common trigonometric functions. In any right triangle , the cosine of an angle is the length of the adjacent side (A) divided by the length of the hypotenuse (H).
