Solution 34752: Calculating Secant, Cosecant, and Cotangent Using the TI-84 Plus C Silver Edition Graphing Handheld.
How do I calculate secant, cosecant and cotangent using a TI-84 Plus C Silver Edition?
The TI-84 Plus C Silver Edition does not have built-in secant, cosecant and cotangent trigonometric functions. To compute these trigonometric functions, use the properties of trigonometric functions which are listed below.
cosecant(x) = csc(x) = 1/sin(x) = sin(x)-1
secant(x) = sec(x) = 1/cos(x) = cos(x)-1
cotangent(x) = cot(x) = 1/tan(x) = tan(x)-1
Example: Solve for the cosecant of 31.67 degrees.
• Be sure the calculator is set to Degree mode before beginning. To do this, press the [MODE] key, move the cursor to DEGREE and press [ENTER].
• Press [2ND] [QUIT] to return to the home screen.
• Press [SIN]   [.]   [)].
• Press [x-1] [ENTER] to complete the calculation.
This will return 1.904667232 which is the cosecant of 31.67 degrees.
Please see the TI-84 Plus C Silver Edition guidebook for additional information.