Answer:
This may help but I think you mean cosine function it means
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.
(this isnt mine its off the wiki page.)
