e = sin(x).series(x, 0, 8);
d = cos(x).series(x, 0, 7);
ed = e.diff(x);
- ed = static_cast<series *>(ed.bp)->convert_to_poly();
- d = static_cast<series *>(d.bp)->convert_to_poly();
+ ed = series_to_poly(ed);
+ d = series_to_poly(d);
if ((ed - d).compare(ex(0)) != 0) {
clog << "derivative of " << e << " by " << x << " returned "