d = log(a*x) + b/a*log(x)*x - pow(b/a, 2)/2*pow(log(x)*x, 2) + Order(pow(x, 3));
result += check_series(e, 0, d, 3);
+ e = pow((x+a), b);
+ d = pow(a, b) + (pow(a, b)*b/a)*x + (pow(a, b)*b*b/a/a/2 - pow(a, b)*b/a/a/2)*pow(x, 2) + Order(pow(x, 3));
+ result += check_series(e, 0, d, 3);
+
return result;
}