HP 35s HP 35s scientific calculator - User Guide - Page 78

Setting the Angular Mode The angular mode specifies which unit of measure to assume for angles used in trigonometric functions. The mode does not convert numbers already present (see "Conversion Functions" later in this chapter). 360 degrees = 2π radians = 400 grads To set an angular mode, press 9. A menu will be displayed from which you can select an option. Option  Description Sets degree mode, which uses decimal degrees rather than hexagesimal degrees (degrees, minutes, seconds) Sets radian mode Sets gradient mode Annunciator none RAD GRAD Trigonometric Functions With x in the display: To Calculate: Sine of x. Cosine of x. Tangent of x. Arc sine of x. Arc cosine of x. Arc tangent of x. Press: Note Calculations with the irrational number π cannot be expressed exactly by the 15-digit internal precision of the calculator. This is particularly noticeable in trigonometry. For example, the calculated sin π (radians) is not zero but -2.0676 × 10-13, a very small number close to zero. 4-4 Real-Number Functions