All the functions must be written in a functional style and must use only the basic scheme functions car, cdr, cons, null, atom, the equality functions, the arithmetic functions, append, and the conditional functions if and cond. be sure to write some code to demonstrate your functions on various inputs. you can place your entire solution into a single scheme (.scm) source file. some possible interpreters: repl. it (recommended for simplicity), guile (for linux environment), dr. scheme/racket, mit/gnu scheme, etc.