Trigonometric.texi

The Trigonometric.texi file says:

    @defvr {Option variable} halfangles
    Default value: @code{false}

    When @code{halfangles} is @code{true},
    half-angles are simplified away.
    @c WHAT DOES THIS STATEMENT MEAN EXACTLY ??
    @c NEEDS EXAMPLES

I think that 'simplified away' is rather clear definition and the following 
simple example could be added:

    (%i1) halfangles;
    (%o1)                                false
    (%i2) sin(x/2);
                                            x
    (%o2)                               sin(-)
                                            2
    (%i3) halfangles : true;
    (%o3)                                true
    (%i4) sin(x/2);
                                   sqrt(1 - cos(x))
    (%o4)                          ----------------
                                       sqrt(2)

-- 
Alexey Beshenov <al at beshenov.ru>
http://beshenov.ru/