diff --git a/04-fibonacci/index.js b/04-fibonacci/index.js
index 37c64cc..be20017 100644
--- a/04-fibonacci/index.js
+++ b/04-fibonacci/index.js
@@ -1,4 +1,7 @@
 export function fibonacci(value) {
   // implementar logica aqui
-  
+    let phi = (1 + Math.sqrt(5))/2;
+    let asymp = Math.pow(phi, value) / Math.sqrt(5);
+
+    return Math.round(asymp);
 }
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