A point situated on a circle with ray A. The cirle has a center that coincides with the origin in the cartesian plane. The angle created by ray A and the point is given by x (radians).
The sine function represents the shift on the y axis of the point by the function of its angle x in radians. The sinus function is defined by the equation f(x) = A sin(x).
The cosine function represents the shift on the x axis of the point by the function of its angle x. The cosine function is defined by the equation f(x) = A cos(x).
These two functions present some common characteristics: