In a trigonometric circle, function f of \(\mathbb{R}\) in \(\mathbb{R}\) under which all angles of rotation x are made to correspond to the y-coordinate of a point P of this circle.
In the illustration above, sin(x) = k, where k is the y-intercept of point P.
Symbol
The symbol for the sine function is “sin” and the image of an angle of rotation x of this function is written as “sin(x)” which is read as “sine x” or “sine of x.”
The argument of the function is a number that represents an angle of rotation (and not a figure).
