function y = myexact(x)
    c2 = (8 - 12*sin(log(2)) - 4*cos(log(2)))/70;
    c1 = 1.1 - c2;
    y = c1*x + c2 ./ x.^2 - 0.3*sin(log(x)) - 0.1*cos(log(x));
end
