The Elementary Functions (F18’s) are the set of functions of one real variable defined recursively as follows: Base cases: The i
dentity function id.x/ WWD x is an F18, any constant function is an F18, the sine function is an F18, Constructor cases: If f; g are F18’s, then so are 1. f C g, fg, 2 g , 2. the inverse function f 1 , 3. the composition f ı g. Prove that the function 1=x is an F18.
