Undefined function 'x0' for input arguments of type 'double'.??

Error in x0(5*n+1)=((Uh*Ah)/Ls)*((Tb0-x0(4*n))/log((Tvc-x0(4*n))/(Tvc-Tb0)));

[ahlem sellami]

i try to evaluate the initial value of an unknown I named x0 (5 * n + 1) with Uh Ah Ls Tvc Tb0 n x0(4*n)are data it

Answer 1

[Thorsten]

You try to evaluate

x0(4*n)

and it seems that x0 is not defined. It could be a variable, if 4*n is an index, or a function. But you have to define it before you can use it; same for all other variables/functions to the right of the =.

[ahlem sellami]

x0(4*n) it is the initial value of t1 which already defined