Solution 11902: Unexpected Results Received using Trigonometric Functions on TI Graphing Products.
Why do I receive an incorrect answer when using trigonometric functions on TI graphing calculators?
The reason that the calculator may not display the expected answer is because it is not using the correct angle mode setting. The instructions below detail how to change the angle mode to Degree on TI graphing calculators.
Procedure for the TI-80, TI-81, TI-82, TI-73, TI-73 Explorer™, TI-83 Family and TI-84 Plus family:
1) Press [MODE]
2) Scroll until the cursor is blinking on Degree (Deg on the TI-81)
3) Press [ENTER]
4) Press [CLEAR] to return to the home screen
Procedure for the TI-85 and TI-86:
1) Press [2nd] [MODE]
2) Scroll until the cursor is blinking on Degree
3) Press [ENTER]
4) Press [2nd [QUIT] to return to the home screen
Procedure for the TI-89 family, TI-92 family, and Voyage™ 200:
1) Press [MODE]
2) Scroll to the Angle menu
3) Press the right or left directional keys to display the Angle menu choices
4) Select DEGREE
5) Press [ENTER] [ENTER] to save the Angle mode setting
Procedure for the TI-Nspire™ Handheld family:
1) Press [HOME] key - this key has a house icon
2) Select 5:Settings >> 2:Settings - choose either 1:General Settings or 2:Graphs & Geomatry
3) Tab to the Angle setting
4) Use the selection pad to select Degree
5) Press [ENTER] [ENTER] to save the setting
Input the problem, and the expected answer should be returned.
Please see the Graphing Model Family guidebooks for additional information.