(define heron-sqrt

1
(define heron-sqrt  (lambda (x)    try some
guess for sqrt(x)--we always pick 1    (try 1
x)))(define try  (lambda (guess x)   if the
guess is good enough   (if (good-enough? guess
x)        then stop and return the old
guess       guess       otherwise, try an
improved guess       (try (improve guess x)
x))))(define good-enough?  (lambda (guess
x)    (lt (abs (- (square guess) x))
0.0001)))(define improve  (lambda (guess
x)    (/ ( guess (/ x guess)) 2.0)))(define
square  (lambda (x) ( x x)))