first commit
diff --git a/sqrt.lsp b/sqrt.lsp
index e69de29..bef1354 100644
--- a/sqrt.lsp
+++ b/sqrt.lsp
@@ -0,0 +1,23 @@
+(defun sqrt-iter (guess x)
+  (if (good-enough? guess x)
+      guess
+      (sqrt-iter (improve guess x)
+                 x)))
+
+(defun improve (guess x)
+  (average guess (/ x guess)))
+
+(defun average (x y)
+  (/ (+ x y)
+     2))
+
+(defun good-enough? (guess x)
+  (< (abs (- (square guess)
+             x))
+     0.001))
+
+(defun square (x)
+  (* x x))
+
+(defun sqrt (x)
+  (sqrt-iter 1.0 x))