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mybook$=%H;  //Workbook name
differentiate -r 2 iy:=[mybook$]1!(A,B);  //Get derivatives
interp1 -r 2 ix:=[mybook$]1!C iy:=[mybook$]1!(A,B);  //interp original data
interp1 -r 2 ix:=[mybook$]1!C iy:=[mybook$]1!(A,D);  //interp derivative data
myx=col(3)[1];  //Contact x
myy=col(5)[1];  //Contact y
myslope=col(6)[1];
myxintercept=myx-myy/myslope;
myyintercept=myy-myx*myslope;
worksheet -a 2;   //add col(7) and col(8) for tangent line
range slopex=col(7);
range slopey=col(8);
wks.col7.type=4;  //set col(7) as X
plotxy [mybook$]1!col(2) plot:=200; //Line plot col(2)
//y1=0;   if you want to have a predetermined bottom
//x2=10;  if you want to have a predetermined right-end
slopex[1]=(y1-myyintercept)/myslope; //x of frame bottom
slopey[1]=y1;  //y of frame bottom
slopex[2]=myx;
slopey[2]=myy;
slopex[3]=x2;  //x of right end of graph frame
slopey[3]=slopex[3]*myslope+myyintercept;  //y at right end
range sline=[mybook$]1!col(8);
layer -i202 sline;  //add Line+Symbol slope plot
slopey[C]$= slope: $(myslope) 
Y intercept: $(myyintercept) 
X intercept: $(myxintercept) 
Bottom X: $(slopex[1])
Bottom Y: $(slopey[1]); //Comment on parameters
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