What is cos pi?

The cosine function (cos) is a trigonometric function that relates the angle measurement in a right triangle to the ratio of the length of the adjacent side to the hypotenuse. The value of cos(pi) refers to the cosine of the angle pi radians or 180 degrees.

In trigonometry, the unit circle is often used to compute cosine values. On the unit circle, cos(pi) corresponds to the x-coordinate of the point where the angle measures pi radians, or in degrees, it corresponds to the x-coordinate of the point on the unit circle where the angle measures 180 degrees.

Since pi is half of a full circle or 180 degrees, the cosine of pi is equal to -1. Therefore, cos(pi) = -1. This means that the adjacent side of a right triangle is negative when the angle is pi radians or 180 degrees.

Cos(pi) can be found in various applications of mathematics and physics. It is used in the calculation of periodic phenomena, such as sound waves, alternating current, and wave functions in quantum mechanics. Additionally, cos(pi) is essential in the computations involving circular motion and vectors.

In summary, cos(pi) is equal to -1, indicating that the cosine of pi radians or 180 degrees is a ratio of -1 between the adjacent side and the hypotenuse in a right triangle.