Хеј Андреј

I made some example for Wiki and bumped into few problems. Take a look at this math region (taking (i+1) derivative):
[MATH lang=eng]el(M,ij)←diff(el(f(x),j),x,i+1)[/MATH]
It is Ok, but if you try to put it in a double for loop, it will be a mess - it does not present properly but it seems to work Ok?
[MATH lang=eng]for(i,range(1,n),for(j,range(1,n),el(M,ij)←diff(el(f(x),j),x,i+1)))[/MATH]
Another thing. This is a part of the worksheet. It is Ok.
[MATH lang=eng]f(U)←mat(e^U,e^{-U},2,1)[/MATH]
[MATH lang=eng]n←rows(f(U))[/MATH]
[MATH lang=eng]for(j,range(0,n-1),for(i,range(0,n-1),el(W,i+1,j+1)←diff(el(f(U),j+1),U,i)))[/MATH]
[MATH lang=eng]W—mat(e^U,1/{e^U},e^U,-1/{e^U},2,2)[/MATH]
But if you put it this way - it won't work. It reported "U - not defined"?
[MATH lang=eng]for(j,range(0,rows(f(U))-1),for(i,range(0,rows(f(U))-1),el(W,i+1,j+1)←diff(el(f(U),j+1),U,i)))[/MATH]
I remember I've noted this some time ago. If you already answered this, sorry.

Regards,
Radovan