Data commit

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

@@ -0,0 +1,17 @@
+function nthroot(n::Integer, r::Real)
+    r < 0 || n == 0 && throw(DomainError())
+    n < 0 && return 1 / nthroot(-n, r)
+    r > 0 || return 0
+    x = r / n
+    prevdx = r
+    while true
+        y = x ^ (n - 1)
+        dx = (r - y * x) / (n * y)
+        abs(dx) ≥ abs(prevdx) && return x
+        x += dx
+        prevdx = dx
+    end
+end
+
+@show nthroot.(-5:2:5, 5.0)
+@show nthroot.(-5:2:5, 5.0) - 5.0 .^ (1 ./ (-5:2:5))