restart;
A1 := diff(arctan(1+x^2), x);
simplify(A1);
A2 := diff(exp(x)/(1+abs(sin(x))^3), x);
simplify(A2) assuming x::real;
help("abs");
A4 := diff((cos(x)+2)^x, x);
A5 := diff(x^2*sin(2*x)*cos(2*x), x);
simplify(A5);
A3 := diff(ln(sin(x)-4), x);