Cos Function Identities
The basic trigonometric identities related to cosine function is mentioned below:
- sin2(x) + cos2(x) = 1
- cos(x + y) = cos(x)cos(y) – sin(x)sin(y)
- cos(x – y) = cos(x)cos(y) + sin(x)sin(y)
- cos(-x) = cos(x)
- cos(x) = 1/sec(x)
- cos 2x = cos2x – sin2x = 1 – 2sin2x = 2cos2x – 1 = (1 – tan2x/1 + tan2x)
- cos 3x = 4cos3x – 3cos x
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Cosine Function
the Cosine function or the cos function in short is one of the six Trigonometric Functions fundamental to trigonometry. Cosine in Trigonometry is given as the ratio of the base to the hypotenuse of a right-angled triangle. Cosine Function is represented as Cos x where x is the angle for which the cosine ratio is calculated. In terms of function, we can say that x is the input or the domain of the cosine function.
It is extensively used in a wide range of subjects like Physics, Geometry, and Engineering among others generally by leveraging its periodic nature. For example, it is used to define the wave nature of sound waves, calculations of electric flux through a plane surface, etc. In this article, we learn in detail about what is cosine function, the domain and range of the cosine function, the period, and the graph of the cosine function.
Table of Content
- What is the Cosine Function?
- Cos in Unit Circle
- Cosine Function Graph
- Inverse of cosine function
- Cosine Function in Calculus
- Cos Function Identities