ANSWER MUST BE IN RACKET PROGRAMMING LANGUAGE

In Racket, write a recursive function called (used-in? x expression). This function will return the "#t" if the given variable "x" is declared as a variable in the "expression", but is not used.

For example,

> (used-in? m '(lambda (m) n))

Returns,

#t because m is declared but not used

> (used-in? m '(lambda (n) lambda (m) m)))

Returns,

#f, because m is declared and used in the given "expression".