HP 48gII hp 48gII_user's manual_English_E_HDPMSG48E67_V2.pdf - Page 51

Angle Measure Trigonometric functions, for example, require arguments representing plane angles. The calculator provides three different Angle Measure modes for working with angles, namely: • Degrees: There are 360 degrees (360o) in a complete circumference, or 90 degrees (90o) in a right angle. This representation is mainly used when doing basic geometry, mechanical or structural engineering, and surveying. • Radians: There are 2π radians (2π r) in a complete circumference, or π/2 radians (π/2 r) in a right angle. This notation is mainly used when solving mathematics and physics problems. This is the default mode of the calculator. • Grades: There are 400 grades (400 g) in a complete circumference, or 100 grades (100 g) in a right angle. This notation is similar to the degree mode, and was introduced in order to "simplify" the degree notation but is seldom used now. The angle measure affects the trig functions like SIN, COS, TAN and associated functions. To change the angle measure mode, use the following procedure: • Press the H button. Next, use the down arrow key, ˜, twice. Select the Angle Measure mode by either using the \key (second from left in the fifth row from the keyboard bottom), or pressing the @CHOOS soft menu key ( B). If using the latter approach, use up and down arrow keys,- ˜, to select the preferred mode, and press the !!@@OK#@ F soft menu key to complete the operation. For example, in the following screen, the Radians mode is selected: Coordinate System Page 1-22