Cosine

Cosine is one of the trigonometric ratios in mathematical subject Trigonometry. The ratio between adjacent side and hypotenuse of a right angle triangle is defined Cosine. Cosine function is usually written in its short form Cos. In fact Cosine is a dependent function and depended on angle of the right angle triangle. In other words, expressing Cosine function with simply Cos is wrong mathematically.

Consider a right angle triangle as shown in the below picture and its sides are opposite side, adjacent side (some people call it as base) and hypotenuse and angle of the right angle triangle is Theta which is denoted with a symbol θ. Now, Cosine function can be written in its short form by integrating the angle i.e Cos θ.

As per the definition of trigonometric function Cosine, we know that the ratio of length of the adjacent side or base and its hypotenuse is Cosine. The same definition can be written in mathematical form as stated below.

Cos θ

=

Length of the Adjacent Side Length of the Hypotenuse

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