how to draw tangent line simulink graph ?

I would like to plot Tangent Line in Simulink MATLAB result . In speed vs time graph. I would like to PLOT A TANGENT LINE in

Kindly help me..

[Fangjun Jiang]

Your question is not clear.

Answer 1

[Chaowei Chen]

function plot_tangent(x,y)

    if nargin<2,
    x=1:0.01:10;y=sin(x);
    end
    s=diff(y)./diff(x);

    f_tangent=@(a,ind)(s(ind)*(a-x(ind))+y(ind));

    x_range=[min(x) max(x)];
    iscontinue=true;
    plot(x,y);
    [gx,gy,mouse]=ginput(1);
    x_gx_diff=abs(x-gx);
    ind=find(x_gx_diff==min(x_gx_diff));
    hold on;
    h=plot(x_range,f_tangent(x_range,ind),'r');
    hold off;
    iscontinue=mouse==1;
while iscontinue    
   [gx,gy,mouse]=ginput(1);
   delete(h);
   x_gx_diff=abs(x-gx);
   ind=find(x_gx_diff==min(x_gx_diff));
   hold on;
   h=plot(x_range,f_tangent(x_range,ind),'r');
   hold off;
   iscontinue=mouse==1;
end

[Chaowei Chen]

you probably can work around with and integrate this code into your simulink application.