Time for an 2014 update…

Task/Nth-root/Julia/nth-root.julia

@@ -0,0 +1,15 @@
+function nthroot(n::Integer, A::Real)
+    A < 0 || n == 0 && throw(DomainError())
+    n < 0 && return 1/nthroot(-n, A)
+    A == 0 && return A
+    x = A / n
+    prevdx = A
+    while true
+        y = x^(n-1)
+        dx = (A - y*x) / (n * y)
+        abs(dx) >= abs(prevdx) && return x
+        x += dx
+        prevdx = dx
+    end
+end
+@vectorize_2arg Number nthroot