Direct derivation of Bessel function with MATLAB

syms x y;% Defining symbols

 steps=str2num(get(handles.edit_steps,'string')) ;% Get order array
    if length(steps)==1% Must be a single curve
        switch get(handles.popupmenu_pick,'value')% Get the type of Bessel function
            case 1          
                y=besselj(steps(1),x);          
            case 2
                y=bessely(steps(1),x);      
        end
        dy=diff(y);% First derivative function
        ddy=diff(dy);% Second derivative function
        x=0.01:0.01:14;
        hold on;
        plot(x,subs(dy),'m');
        plot(x,subs(ddy),'g');
        hold off;
       
    end
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matlab Toolbox can be calculated directly ：BessDerivZerosBisect2,besselzeros,getZerosBesselFunction