From a14449600f613e3c557caff6e0c6c764fbbe24be Mon Sep 17 00:00:00 2001
From: Tobias Eidelpes <tobias@eidelpes.info>
Date: Sat, 5 Nov 2022 12:51:54 +0100
Subject: [PATCH] Add Exercise 2.10

---
 chapter2.lisp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/chapter2.lisp b/chapter2.lisp
index f2bc972..b1cf998 100644
--- a/chapter2.lisp
+++ b/chapter2.lisp
@@ -97,3 +97,11 @@ and upper bound."
   (/ (- (upper-bound x) (lower-bound x))
      2.0))
 
+;; Exercise 2.10
+(defun div-interval (a b)
+  (if (zerop (width-interval b))
+      (error "Cannot divide by 0 width interval")
+   (mul-interval
+    a
+    (make-interval (/ 1.0 (upper-bound b))
+		   (/ 1.0 (lower-bound b))))))