diff --git a/A1/infix-ae.rkt b/A1/infix-ae.rkt
index a87b172..9e173f8 100644
--- a/A1/infix-ae.rkt
+++ b/A1/infix-ae.rkt
@@ -40,7 +40,12 @@
     [(Add l r) (+ (eval l) (eval r))]
     [(Sub l r) (- (eval l) (eval r))]
     [(Mul l r) (* (eval l) (eval r))]
-    [(Div l r) (/ (eval l) (eval r))]))
+    [(Div l r) (if(equal? 0 (eval r))
+                  (cond
+                    [(< 0 (eval l)) +inf.0]
+                    [(> 0 (eval l)) -inf.0]
+                    [else +nan.0])
+                  (/ (eval l) (eval r)))]))
 
 ;; evaluate an AE program contained in an s-expr
 (define (run sx)