Hello waluyo,

I think there is nothing nothing wrong with your results. I suppose you wanted to use these functions on every elements of vector "tt". This should be done this way:
for(i,range(1,length(tt)),line(el(s,i):s(el(tt,i)),el(ds,i):v(el(tt,i)),el(dv,i):a(el(tt,i)),3,1))
s=mat(6,-16,-26,-12,38,5,1)ds=mat(-24,-18,0,30,72,5,1)dv=mat(0,12,24,36,48,5,1)
Pay attention then when you multiply two vectors you will get their scalar product - not the vector which represents the product of their appropriate elements:
tt*tt=30 tt^2=30 sum((el(tt,i)^2),i,1,length(tt))=30

Regards,
Radovan

You are welcome waluyo

Glad that I was of any help. Actually, I also often made mistakes in SMath mixing it with Mathcad, as well as you did.

Regards,
Radovan