INPUT & EVAL()

[DrD]

I have tried this:

Code:


EXPORT test()
BEGIN  

  LOCAL d2ydx2, x, y, t;

  INPUT({ {x, [8], {35,60,0}},                 
          {y, [8], {35,60,1}},
          {t, [8], {35,60,2}} },
                       
          "Parametric Equation 2nd Derivative", 
          {"x = ", "y = ", "Parameter = "}, 
          {"Enter the x-function ", "Enter the y-function", "Enter the parameter variable"},           
          {QUOTE(t^2-4),QUOTE(t^3-3*t),QUOTE(t)}, 
          {QUOTE(t^2-4),QUOTE(t^3-3*t),QUOTE(t)} );

  d2ydx2:=normal(diff((diff(y,t))/(diff(x,t)),t)/(diff(x,t))); //  Second derivative 
  RETURN d2ydx2; 

END;

The default {reset,initial} parameters work, however, manually inputting new, (or changing existing) values, doesn't work. There are probably better ways to do this, but this is where I am at the moment...

-Dale-