sin, cos, tan, asin, acos, atan, atan2 \- trigonometric functions
return trigonometric functions of radian arguments.
returns the arc sin in the range \-\(*p/2 to \(*p/2.
returns the arc cosine in the range 0 to \(*p.
returns the arc tangent of
in the range \-\(*p/2 to \(*p/2.
.I sign(y)*(\(*p \- atan(|y/x|))
Arguments of magnitude greater than 1 cause
to return the reserved operand on the VAX;
Robert P. Corbett, W. Kahan, Stuart McDonald, Kwok-Choi Ng