;;;;; Gambit v4.8.8

> (sqrt -inf.0+1.0i)
0.+inf.0i
> (sqrt -inf.0-1.0i)
0.-inf.0i
> 

;;;;; Chez Scheme Version 9.5.1

> (sqrt -inf.0+1.0i)
0.0+inf.0i
> (sqrt -inf.0-1.0i)
0.0-inf.0i
> 

;;;;; GNU Guile 2.2.3

scheme@(guile-user)> (sqrt -inf.0+1.0i)
$1 = 0.0+inf.0i
scheme@(guile-user)> (sqrt -inf.0-1.0i)
$2 = 0.0-inf.0i

;;;; This is SBCL 1.4.5.debian, an implementation of ANSI Common Lisp.

* (sqrt #C( #.SB-EXT:DOUBLE-FLOAT-NEGATIVE-INFINITY 1.0))
#C(0.0d0 #.SB-EXT:DOUBLE-FLOAT-POSITIVE-INFINITY)
* (sqrt #C( #.SB-EXT:DOUBLE-FLOAT-NEGATIVE-INFINITY -1.0))
#C(0.0d0 #.SB-EXT:DOUBLE-FLOAT-NEGATIVE-INFINITY)

;;; Gambit v4.8.8

> (map (lambda (im) (sqrt (make-rectangular 0 im))) (list 2 8 18 32 50 72 98 128))
(1+i 2+2i 3+3i 4+4i 5+5i 6+6i 7+7i 8+8i)
> 

;;; Chez Scheme Version 9.5.1

> (map (lambda (im) (sqrt (make-rectangular 0 im))) (list 2 8 18 32 50 72 98 128))
(1+1i 2+2i 3+3i 4+4i 5+5i 6+6i 7+7i 8+8i)
> 

;;; GNU Guile 2.2.3

scheme@(guile-user)> (map (lambda (im) (sqrt (make-rectangular 0 im))) (list 2 8 18 32 50 72 98 128))
$1 = (1.0+1.0i 2.0+2.0i 3.0+3.0i 4.0+4.0i 5.0+5.0i 6.0+6.0i 7.0+7.0i 8.0+8.0i)


;;; This is SBCL 1.4.5.debian, an implementation of ANSI Common Lisp.

* (mapcar (lambda (x) (sqrt (complex 0 x))) (list 2 8 18 32 50 72 98 128))

(#C(1.0 1.0) #C(2.0 2.0) #C(3.0 3.0) #C(4.0 4.0) #C(5.0 5.0) #C(6.0 6.0)
 #C(7.0 7.0) #C(8.0 8.0))