hi, why the result of g(2),g(3),g(4) is 3^n,3^n,3^n ? ......... load(solve_rec); rec:f(n)=3*f(n-1); s:solve_rec(rec,f(n),f(1)=3); g(n):= rhs(s); g(2);g(3);g(4); -->3^n,3^n,3^n i know that define(g(n),rhs(s)) works ........ f(x):= x^2; i(y):= rhs(last( solve(f(x)=y,x))); i(2);i(3);i(4); Here works! ........ thanks.