Bessel plotting problem



I have an expression involving 2 bessel functions and no matter what I do I cannot get it to plot the expression.  The bessel_y and the bessel_j functions are both in the expression and so is %i so I just want the realpart.  

I have tried this.

set_plot_option([plot_realpart,true]);

plot2d(-(%i/2+sqrt(3)/2)*%i*'(bessel_y(1/6,-x^3/3))+(bessel_j(1/6,-x^3/3))*sqrt(x),[x,.001,2],[plot_format,gnuplot]),orthopoly_returns_intervals : false;


and I have tried this

plot2d(-(%i/2+sqrt(3)/2)*%i*'(bessel_y(1/6,-x^3/3))+'(bessel_j(1/6,-x^3/3))*sqrt(x),[x,.001,2],[plot_format,gnuplot]),orthopoly_returns_intervals : false;

and this

plot2d(-(%i/2+sqrt(3)/2)*%i*(('bessel_y(1/6,-x^3/3)+'bessel_j(1/6,-x^3/3)))*sqrt(x),[x,.001,2],[plot_format,gnuplot]),orthopoly_returns_intervals : false;

Does anyone know what I am not doing right?  Non of the above work, I get no plot window.

Thanks,

Rich