_Code:

^{Graph := NULL; for i from 0 to N-1 do for j from 0 to 10 do if j <= finite_element_xi[i] and finite_element_xi[i] <= j+1 then finite_element_sigma[i] := evalf(finite_element_epsilon[i]*R(j)); p := plot(finite_element_sigma[i](x), x = finite_element_xi[i] .. finite_element_xi[i+1]); Graph := display(Graph, p) end if end do end do;
Error, (in plot) illegal use of an object as a name}
I don't understand how to draw a graph for sigma