Made sinh return zero inputs unchanged (fixes failing test case)

2012-06-06 10:52:29 -06:00 · 2012-06-06 10:52:29 -06:00 · b7ff3eb1fb
commit b7ff3eb1fb
parent fdb722dcb1
1 changed files with 2 additions and 1 deletions
--- a/collects/racket/math.rkt
+++ b/collects/racket/math.rkt
@ -56,7 +56,8 @@
  ;; complex hyperbolic functions
  (define (sinh z)
    (unless (number? z) (raise-argument-error 'sinh "number?" z))
-    (cond [(real? z)
+    (cond [(= z 0)  z]    ; preserve 0, 0.0, -0.0, 0.0f0, 0.0+0.0i, etc.
+          [(real? z)
           (let loop ([z z])
             (cond [(z . < . 0)  (- (loop (- z)))]
                   [else  (/ (- (exp z) (exp (- z))) 2)]))]