> ?coefficients
Try one of the following topics:


        {coeffs, collect, binomial, combinat[multinomial], liesymm[Eta],

            NPspinor[rewrite], linalg[hadamard], projgeom[fpconic]}
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> ?coeffs
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> ?coeff
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> L := 3*x-2*y+5;

                               L := 3 x - 2 y + 5
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> coeff(L, y);

                                       -2
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> coeff(L, 1);
Error, wrong number (or type) of parameters in function coeff

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> coeff(L);
Error, wrong number (or type) of parameters in function coeff

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> coeff(L, x, 0);

                                    - 2 y + 5
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> subs({x=0, y=0}, L);

                                        5
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> read (`public/Maple/convert.mpl`):

impl2parm :=

  proc(impl_line)
  local a,b,c;
      a := coeff(impl_line,x);
      b := coeff(impl_line,y);
      c := subs({x = 0,y = 0},impl_line);
      if b = 0 then RETURN([-c/a,t]) else RETURN([t,-a/b*t-c/b]) fi
  end

on line 16, syntax error:
   y1 := subs(t=0, yt), y2 := subs(t=1, yt);
                            ^

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> impl2parm(x-y);

                                     [t, t]
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> impl2parm(x-1/2);

                                    [1/2, t]
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> impl2parm(y-1/2);

                                    [t, 1/2]
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> plot([2*t/(1+t^2), (1-t^2)/(1+t^2), t=-10..10]);
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> ?limit
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> limit((1-t^2)/(1+t^2), t=infinity);

                                       -1
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> read(`public/Maple/convert.mpl`);

impl2parm :=

  proc(impl_line)
  local a,b,c;
      a := coeff(impl_line,x);
      b := coeff(impl_line,y);
      c := subs({x = 0,y = 0},impl_line);
      if b = 0 then RETURN([-c/a,t]) else RETURN([t,-a/b*t-c/b]) fi
  end


parm2impl := proc(parm_line)
             local xt,yt,x1,y1,x2,y2;
                 xt := op(1,parm_line);
                 yt := op(2,parm_line);
                 x1 := subs(t = 0,xt);
                 x2 := subs(t = 1,xt);
                 y1 := subs(t = 0,yt);
                 y2 := subs(t = 1,yt);
                 expand((x2-x1)*(y-y1)-(y2-y1)*(x-x1))
             end

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> parm2impl([t,t]);

                                      y - x
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> parm2impl([1/2, t]);

                                    - x + 1/2
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> impl2parm(3*x-2*y+5);

                                [t, 3/2 t + 5/2]
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> parm2impl(");

                                 y - 5/2 - 3/2 x
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> parm2impl([2+t, -1-t]);

                                    y - 1 + x
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>