GNU Emacs Calc 2.02 Manual
7.4.1 Angular Modes
The Calculator supports three notations for angles: radians, degrees,
and degrees-minutes-seconds. When a number is presented to a function
like sin that requires an angle, the current angular mode is
used to interpret the number as either radians or degrees. If an HMS
form is presented to sin, it is always interpreted as
degrees-minutes-seconds.
Functions that compute angles produce a number in radians, a number in
degrees, or an HMS form depending on the current angular mode. If the
result is a complex number and the current mode is HMS, the number is
instead expressed in degrees. (Complex-number calculations would
normally be done in radians mode, though. Complex numbers are converted
to degrees by calculating the complex result in radians and then
multiplying by 180 over
pi.)
The m r (calc-radians-mode), m d (calc-degrees-mode),
and m h (calc-hms-mode) commands control the angular mode.
The current angular mode is displayed on the Emacs mode line.
The default angular mode is degrees.
