# terminal ray

Let an angle whose in radians is $\theta$ be placed the Cartesian plane such that one of its rays $R_{1}$ corresponds to the nonnegative $x$ axis and one can go from the point $(1,0)$ to the point that is the intersection of the other ray $R_{2}$ of the angle with the circle $x^{2}+y^{2}=1$ by traveling exactly $\theta$ units on the circle. (If $\theta$ is positive, the distance should be traveled counterclockwise; otherwise, the distance $|\theta|$ should be traveled clockwise. Also, note that “other ray” is used quite loosely, as it may also correspond to the nonnegative $x$ axis also.) Then $R_{2}$ is the terminal ray of the angle.

The picture below shows the terminal ray $R_{2}$ of the angle $\displaystyle\theta=\frac{2\pi}{3}$.

Title terminal ray TerminalRay 2013-03-22 16:06:11 2013-03-22 16:06:11 Wkbj79 (1863) Wkbj79 (1863) 12 Wkbj79 (1863) Definition msc 51-01 Trigonometry CyclometricFunctions