The given angle within the circle can be changed by moving the α' slider at the top (-2880 through 2880). Check boxes will display different content, it is advisable to limit your check to at most 2 or 3 at a time. Follow the instructions below initially.[br][br]All coterminal angles are an angles of different measure that share the same initial side and terminal side.[br][br]A reference angle is the acute angle formed by the terminal side and the x-axis. (The only values a calculator recalls are the reference angles.)[br][br]SohCahToa is a mnemonic device to assist in remembering the sine, cosine, and tangent ratios. (Memory Trigger)[br][br]The vectors of the sine and cosine are a visual representation of the values of the sine and cosine functions.

1) Move slider left and right to observe the line that move and the x- and y-values on the point on the end[br]2) Check the Vectors box to observe the values and segment lengths that are displayed {un-check box}[br]3) Check the Positive Coterminal box; this displays the positive coterminal angle between 0° and 360° for the α' angle {un-check box}[br]4) Check the Negative Coterminal box; this displays the negative coterminal angle between -360° and 0° for the α' angle {un-check box}[br]5) Check the Reference Angle box; this will display the reference angle for any given angle {un-check box}[br]6) Checking the Functions box reveals the mneumonic SohCahToa check box; checking SohCahToa allows the user to compare the coordinates on the circle to the value of the sine, cosine, and tangent functions.[br]7) When you are ready to view the reciprocal trigonometric functions, click the check box[br]8) Be sure to notice when a function is undefine. Can you explain why?[br][br]While working with the trigonometric functions, the Vectors and Reference Angle check boxes assist examinations of the functions.[br][br]Additional Resources include: http://en.wikipedia.org/wiki/Angle