update

Task/Nth-root/Racket/nth-root.rkt

@@ -0,0 +1,15 @@
+#lang racket
+
+(define (nth-root number root (tolerance 0.001))
+  (define (acceptable? next current)
+    (< (abs (- next current)) tolerance))
+
+  (define (improve current)
+    (/ (+ (* (- root 1) current) (/ number (expt current (- root 1)))) root))
+
+  (define (loop current)
+    (define next-guess (improve current))
+    (if (acceptable? next-guess current)
+        next-guess
+        (loop next-guess)))
+  (loop 1.0))