static RCP<const Basic> diff(const ATan &self,
const RCP<const Symbol> &x) {
return mul(div(one, add(one, pow(self.get_arg(), i2))),
self.get_arg()->diff(x));
}
void bvisit(const ATan &x) {
apply(result_, *(x.get_arg()));
mpfr_atan(result_, result_, rnd_);
}
