1 files changed, 14 insertions, 0 deletions
diff --git a/coding-exercises/1/chapter115.rkt b/coding-exercises/1/chapter115.rkt
new file mode 100644
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--- /dev/null
+++ b/coding-exercises/1/chapter115.rkt
@@ -0,0 +1,14 @@
+#lang sicp
+(define counter (box 0))
+
+(define (cube x) (* x x x))
+(define (p x) 
+  (set-box! counter (+ (unbox counter) 1))
+  (- (* 3 x) (* 4 (cube x))))
+(define (sine angle)
+  (if (not (> (abs angle) 0.1))
+    angle
+    (p (sine (/ angle 3)))))
+(sine 1250.0)
+(println "\n")
+(println (unbox counter))