Function: ratnumer (<expr>) Returns the numerator of <expr>, after coercing <expr> to a canonical rational expression (CRE). The return value is a CRE.
<expr> is coerced to a CRE by
rat if it is not already a CRE. This conversion may change the form of <expr> by putting all terms over a common denominator.
num is similar, but returns an ordinary expression instead of a CRE. Also,
num does not attempt to place all terms over a common denominator, and thus some expressions which are considered ratios by
ratnumer are not considered ratios by
(%o1) true (%i2)