Add net/ricketyspace/sicp/one/thirtyeight.scm.

1 files changed, 19 insertions, 0 deletions

diff --git a/net/ricketyspace/sicp/one/thirtyeight.scm b/net/ricketyspace/sicp/one/thirtyeight.scm
new file mode 100644
index 0000000..be5288a
--- /dev/null
+++ b/net/ricketyspace/sicp/one/thirtyeight.scm
@@ -0,0 +1,19 @@
+;;;; Under Creative Commons Attribution-ShareAlike 4.0
+;;;; International. See
+;;;; <https://creativecommons.org/licenses/by-sa/4.0/>.
+
+(define-module (net ricketyspace sicp one thirtyeight)
+  #:use-module (net ricketyspace sicp one thirtyseven)
+  #:export (euler-minus-2))
+
+(define (euler-minus-2)
+  (define (n i) 1.0)
+  (define (d i) (cond ((= i 1) 1)
+                      ((= (remainder i 3) 2) (* (+ (quotient i 3) 1) 2))
+                      (else 1)))
+  (cont-frac-rec n d 21))
+
+;;; Guile REPL
+;;; scheme@(guile-user)> ,use (net ricketyspace sicp one thirtyeight)
+;;; scheme@(guile-user)> (euler-minus-2)
+;;; $25 = 0.7182818284590453