4.1 (+ 8 (* 2 12))
4.2 A->(B +)->(C *)
4.4 (1) two return values
(2) wrong expression
(3) no argument
(4) less argument
(5) incorrect argument
4.5 (define (ftoc f)
(* (/ 5 9)(- f 32)))
(define (ctof c)
(+ 32 (* c (/ 9 5))))
4.6 (define (fourth x)
(* x x x x))
(define (fourth x)
(square (square x)))
4.7 (define (abs x)
(square (square x)))
4.8 (define (scientific x y)
(* x (expt 10 y)))
(define (sci-e x)
{floor (+ 0.5 (/ (log x) (log 10)))})
(define (sci-c m)
{/ m (expt 10 (sci-e m))})
(define (tip fee)
{- (ceiling (* 1.15 fee)) fee})
4.9 (define (discount x y)
{* x (- 1 (/ y 100))})
4.10 (define (tip fee)
{- (ceiling (* 1.15 fee)) fee})