Angular js Div show only for 3 seconds

i am new in angular js. i done with div hide and show. just i want to know how to hide or show div for 3 seconds only. here i attaching my code which i used.

html code:

<div ng-hide="loginAlertMessage">Dynamic user feedback message comes here.</div>    
<a ng-click="forgotPassword()">Forgot Password?</a>

angular js code:

$scope.loginAlertMessage = true;

    $scope.forgotPassword = function () {
         $scope.loginAlertMessage=false;    
    };