
Re: Very simple question
Posted:
Apr 9, 2014 4:46 AM


On 4/9/2014 3:14 AM, Ste[hen Gray wrote: > I've been away from Mathematica for about 7 years. > Can anyone tell me why function fx gives an error message but fy does > not? They look functionally the same to me. > Please send me an email about this. > > fx[ptl_] := Module[{x1, y1, x2, y2, x3, y3}, > Print[pt1]; > x1 = pt1[[1, 1]]; y1 = pt1[[1, 2]]; > x2 = pt2[[2, 1]]; y2 = pt2[[2, 2]]; > x3 = pt3[[3, 1]]; y3 = pt3[[3, 2]]; > Print[x1, y1, x2, y2, x3, y3]; > ] > fx[{{1, 2}, {3, 5}, {4, 7}}] >
First problem: the input is "ptl". Then inside the module you use "pt1".
One uses the lower case letter L, and the second uses the number 1.
The second problem: There is no such thing as "pt2" and "pt3" anywhere. Where did these come from?
> fy[pt1_] := Module[{zz, x1, y1, x2, y2, x3, y3}, > zz = pt1;
This one uses "pt1" as input and uses "pt1" inside the module. So this one is correct.
Nasser

