22 if (car(p1
) == symbol(COS
)) {
32 stop("arccos function argument is not in the interval [-1,1]");
38 // if p1 == 1/sqrt(2) then return 1/4*pi (45 degrees)
40 if (isoneoversqrttwo(p1
)) {
48 // if p1 == -1/sqrt(2) then return 3/4*pi (135 degrees)
50 if (isminusoneoversqrttwo(p1
)) {
58 if (!isrational(p1
)) {