How do I know if my calculator is in radians or degrees?
Look at the top of the screen. fx-991EX: the indicator at the top shows the angle unit.fx-991CW: the status bar shows the angle unit.fx-CG50: the status bar shows Deg or Rad.Or type sin(90): 1 means degrees; 0.894 means radians.
A trig answer that is badly wrong is nearly always the wrong angle mode. The quickest test, on any calculator: work out sin(90). An answer of 1 means degrees; 0.894 (to 3 s.f.) means radians.
When do I need radians, and when degrees?
Use radians for calculus with trig functions (differentiating or integrating sin x, cos x, tan x), small-angle approximations, arc length and sector area with θ in radians (s = rθ, A = ½r²θ), and whenever an angle is written with π (such as π/6) or with no degree sign. Use degrees for triangles (sine rule, cosine rule, ½ab sin C), bearings and any angle written with °.
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How do I know if my fx-991EX is in radians or degrees?
An indicator at the top of the screen shows the current Angle Unit (degree, radian or gradian).
How do I change the fx-991EX to radians or degrees?
- Press SHIFT MENU (SETUP).
- Press 2 (Angle Unit).
- Press 1 (Degree) or 2 (Radian).
Source: Casio fx-991EX / fx-570EX User's Guide (PDF) · Casio fx-991EX Quick Start Guide (PDF)
How do I know if my fx-991CW is in radians or degrees?
An indicator in the status bar at the top of the screen shows the current Angle Unit (degree, radian or gradian).
How do I change the fx-991CW to radians or degrees?
- In a calculator app, press SETTINGS.
- Choose Calc Settings → Angle Unit.
- Choose Degree or Radian.
Casio's guide: when a derivative or integral has a trig function in it, set the Angle Unit to Radian.
Source: Casio fx-991CW User's Guide: Using the SETTINGS Menu
How do I know if my fx-CG50 is in radians or degrees?
Look at the status bar at the top of the screen: it shows Deg, Rad or Gra.
How do I change the fx-CG50 to radians or degrees?
- Press SHIFT MENU (SET UP).
- Move down to Angle.
- Press the function key for Deg or Rad, then EXIT.
Source: Casio fx-CG50 Software User's Guide (PDF): SET UP and Reset · Casio UK: Getting started with the fx-CG50, guide for teachers
How do I know if my TI-84 Plus CE is in radians or degrees?
The status bar at the top of the screen shows RADIAN or DEGREE.
How do I change the TI-84 Plus CE to radians or degrees?
- Press mode.
- Move down to the RADIAN DEGREE line.
- Move across to the one you want and press enter.
How do I know if my TI-Nspire CX II is in radians or degrees?
The angle mode (RAD or DEG) is shown at the top of the page you are on.
How do I change the TI-Nspire CX II to radians or degrees?
- Press home/on and choose Settings → Document Settings.
- Set Angle to Radian or Degree.
- Choose OK.
Graphs and Geometry pages have their own angle settings: TI says the Graphing Angle starts as Radian and the Geometry Angle as Degree. Set them to Auto to follow the document's angle.
Source: TI-Nspire CX Student Software Guidebook: Document Settings · TI-Nspire guidebook: Changing Graphs & Geometry Settings
Questions
How do I know if my calculator is in radians or degrees?
Look at the top of the screen: the calculators on this page show the angle unit there. Or work out sin(90): 1 means degrees, 0.894 means radians.
How do I change the fx-991EX to radians?
Press SHIFT MENU (SETUP). Press 2 (Angle Unit). Press 1 (Degree) or 2 (Radian).
How do I change the fx-991CW to radians?
In a calculator app, press SETTINGS. Choose Calc Settings → Angle Unit. Choose Degree or Radian.
How do I change the fx-CG50 to radians?
Press SHIFT MENU (SET UP). Move down to Angle. Press the function key for Deg or Rad, then EXIT.
How do I change the TI-84 Plus CE to radians?
Press mode. Move down to the RADIAN DEGREE line. Move across to the one you want and press enter.
How do I change the TI-Nspire CX II to radians?
Press home/on and choose Settings → Document Settings. Set Angle to Radian or Degree. Choose OK.
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Every keystroke on this page comes from the manufacturer's own guide for that model, and every exam rule from the exam board's own document; each section names its source. Where we could not find a step in one of those documents, we have left it out. A Level Math Revision is independent and is not connected to Casio, Texas Instruments or any exam board.